diff --git a/hostapd/ctrl_iface.c b/hostapd/ctrl_iface.c
index 14f128bb2..4ed3decf7 100644
--- a/hostapd/ctrl_iface.c
+++ b/hostapd/ctrl_iface.c
@@ -246,14 +246,14 @@ static int hostapd_ctrl_iface_wps_check_pin(
 		if (!wps_pin_valid(pin_val)) {
 			wpa_printf(MSG_DEBUG, "WPS: Invalid checksum digit");
 			ret = os_snprintf(buf, buflen, "FAIL-CHECKSUM\n");
-			if (ret < 0 || (size_t) ret >= buflen)
+			if (os_snprintf_error(buflen, ret))
 				return -1;
 			return ret;
 		}
 	}
 
 	ret = os_snprintf(buf, buflen, "%s", pin);
-	if (ret < 0 || (size_t) ret >= buflen)
+	if (os_snprintf_error(buflen, ret))
 		return -1;
 
 	return ret;
@@ -584,7 +584,7 @@ static int hostapd_ctrl_iface_wps_get_status(struct hostapd_data *hapd,
 	ret = os_snprintf(pos, end - pos, "PBC Status: %s\n",
 			  pbc_status_str(hapd->wps_stats.pbc_status));
 
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -594,7 +594,7 @@ static int hostapd_ctrl_iface_wps_get_status(struct hostapd_data *hapd,
 			   (hapd->wps_stats.status == WPS_STATUS_FAILURE ?
 			    "Failed" : "None")));
 
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -605,7 +605,7 @@ static int hostapd_ctrl_iface_wps_get_status(struct hostapd_data *hapd,
 				  "Failure Reason: %s\n",
 				  wps_ei_str(hapd->wps_stats.failure_reason));
 
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -614,7 +614,7 @@ static int hostapd_ctrl_iface_wps_get_status(struct hostapd_data *hapd,
 		ret = os_snprintf(pos, end - pos, "Peer Address: " MACSTR "\n",
 				  MAC2STR(hapd->wps_stats.peer_addr));
 
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -1067,7 +1067,7 @@ static int hostapd_ctrl_iface_get_config(struct hostapd_data *hapd,
 			  MAC2STR(hapd->own_addr),
 			  wpa_ssid_txt(hapd->conf->ssid.ssid,
 				       hapd->conf->ssid.ssid_len));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -1076,7 +1076,7 @@ static int hostapd_ctrl_iface_get_config(struct hostapd_data *hapd,
 			  hapd->conf->wps_state == 0 ? "disabled" :
 			  (hapd->conf->wps_state == 1 ? "not configured" :
 			   "configured"));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -1084,7 +1084,7 @@ static int hostapd_ctrl_iface_get_config(struct hostapd_data *hapd,
 	    hapd->conf->ssid.wpa_passphrase) {
 		ret = os_snprintf(pos, end - pos, "passphrase=%s\n",
 				  hapd->conf->ssid.wpa_passphrase);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -1096,7 +1096,7 @@ static int hostapd_ctrl_iface_get_config(struct hostapd_data *hapd,
 		wpa_snprintf_hex(hex, sizeof(hex),
 				 hapd->conf->ssid.wpa_psk->psk, PMK_LEN);
 		ret = os_snprintf(pos, end - pos, "psk=%s\n", hex);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -1104,39 +1104,39 @@ static int hostapd_ctrl_iface_get_config(struct hostapd_data *hapd,
 
 	if (hapd->conf->wpa && hapd->conf->wpa_key_mgmt) {
 		ret = os_snprintf(pos, end - pos, "key_mgmt=");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 
 		if (hapd->conf->wpa_key_mgmt & WPA_KEY_MGMT_PSK) {
 			ret = os_snprintf(pos, end - pos, "WPA-PSK ");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
 		if (hapd->conf->wpa_key_mgmt & WPA_KEY_MGMT_IEEE8021X) {
 			ret = os_snprintf(pos, end - pos, "WPA-EAP ");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
 #ifdef CONFIG_IEEE80211R
 		if (hapd->conf->wpa_key_mgmt & WPA_KEY_MGMT_FT_PSK) {
 			ret = os_snprintf(pos, end - pos, "FT-PSK ");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
 		if (hapd->conf->wpa_key_mgmt & WPA_KEY_MGMT_FT_IEEE8021X) {
 			ret = os_snprintf(pos, end - pos, "FT-EAP ");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
 #ifdef CONFIG_SAE
 		if (hapd->conf->wpa_key_mgmt & WPA_KEY_MGMT_FT_SAE) {
 			ret = os_snprintf(pos, end - pos, "FT-SAE ");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
@@ -1145,13 +1145,13 @@ static int hostapd_ctrl_iface_get_config(struct hostapd_data *hapd,
 #ifdef CONFIG_IEEE80211W
 		if (hapd->conf->wpa_key_mgmt & WPA_KEY_MGMT_PSK_SHA256) {
 			ret = os_snprintf(pos, end - pos, "WPA-PSK-SHA256 ");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
 		if (hapd->conf->wpa_key_mgmt & WPA_KEY_MGMT_IEEE8021X_SHA256) {
 			ret = os_snprintf(pos, end - pos, "WPA-EAP-SHA256 ");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
@@ -1159,20 +1159,20 @@ static int hostapd_ctrl_iface_get_config(struct hostapd_data *hapd,
 #ifdef CONFIG_SAE
 		if (hapd->conf->wpa_key_mgmt & WPA_KEY_MGMT_SAE) {
 			ret = os_snprintf(pos, end - pos, "SAE ");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
 #endif /* CONFIG_SAE */
 		if (hapd->conf->wpa_key_mgmt & WPA_KEY_MGMT_IEEE8021X_SUITE_B) {
 			ret = os_snprintf(pos, end - pos, "WPA-EAP-SUITE-B ");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
 
 		ret = os_snprintf(pos, end - pos, "\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -1180,14 +1180,14 @@ static int hostapd_ctrl_iface_get_config(struct hostapd_data *hapd,
 	if (hapd->conf->wpa) {
 		ret = os_snprintf(pos, end - pos, "group_cipher=%s\n",
 				  wpa_cipher_txt(hapd->conf->wpa_group));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
 
 	if ((hapd->conf->wpa & WPA_PROTO_RSN) && hapd->conf->rsn_pairwise) {
 		ret = os_snprintf(pos, end - pos, "rsn_pairwise_cipher=");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 
@@ -1198,14 +1198,14 @@ static int hostapd_ctrl_iface_get_config(struct hostapd_data *hapd,
 		pos += ret;
 
 		ret = os_snprintf(pos, end - pos, "\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
 
 	if ((hapd->conf->wpa & WPA_PROTO_WPA) && hapd->conf->wpa_pairwise) {
 		ret = os_snprintf(pos, end - pos, "wpa_pairwise_cipher=");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 
@@ -1216,7 +1216,7 @@ static int hostapd_ctrl_iface_get_config(struct hostapd_data *hapd,
 		pos += ret;
 
 		ret = os_snprintf(pos, end - pos, "\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -1323,7 +1323,7 @@ static int hostapd_ctrl_iface_get(struct hostapd_data *hapd, char *cmd,
 
 	if (os_strcmp(cmd, "version") == 0) {
 		res = os_snprintf(buf, buflen, "%s", VERSION_STR);
-		if (res < 0 || (unsigned int) res >= buflen)
+		if (os_snprintf_error(buflen, res))
 			return -1;
 		return res;
 	}
diff --git a/hostapd/hlr_auc_gw.c b/hostapd/hlr_auc_gw.c
index c041887ec..42d59dba7 100644
--- a/hostapd/hlr_auc_gw.c
+++ b/hostapd/hlr_auc_gw.c
@@ -711,7 +711,7 @@ static int gsm_auth_req(char *imsi, char *resp, size_t resp_len)
 	rend = resp + resp_len;
 	rpos = resp;
 	ret = os_snprintf(rpos, rend - rpos, "GSM-AUTH-RESP %s", imsi);
-	if (ret < 0 || ret >= rend - rpos)
+	if (os_snprintf_error(rend - rpos, ret))
 		return -1;
 	rpos += ret;
 
@@ -737,7 +737,7 @@ static int gsm_auth_req(char *imsi, char *resp, size_t resp_len)
 
 	printf("No GSM triplets found for %s\n", imsi);
 	ret = os_snprintf(rpos, rend - rpos, " FAILURE");
-	if (ret < 0 || ret >= rend - rpos)
+	if (os_snprintf_error(rend - rpos, ret))
 		return -1;
 	rpos += ret;
 
diff --git a/hostapd/hostapd_cli.c b/hostapd/hostapd_cli.c
index 612176293..a581b44c5 100644
--- a/hostapd/hostapd_cli.c
+++ b/hostapd/hostapd_cli.c
@@ -596,7 +596,7 @@ static int hostapd_cli_cmd_disassoc_imminent(struct wpa_ctrl *ctrl, int argc,
 
 	res = os_snprintf(buf, sizeof(buf), "DISASSOC_IMMINENT %s %s",
 			  argv[0], argv[1]);
-	if (res < 0 || res >= (int) sizeof(buf))
+	if (os_snprintf_error(sizeof(buf), res))
 		return -1;
 	return wpa_ctrl_command(ctrl, buf);
 }
@@ -616,7 +616,7 @@ static int hostapd_cli_cmd_ess_disassoc(struct wpa_ctrl *ctrl, int argc,
 
 	res = os_snprintf(buf, sizeof(buf), "ESS_DISASSOC %s %s %s",
 			  argv[0], argv[1], argv[2]);
-	if (res < 0 || res >= (int) sizeof(buf))
+	if (os_snprintf_error(sizeof(buf), res))
 		return -1;
 	return wpa_ctrl_command(ctrl, buf);
 }
@@ -634,7 +634,7 @@ static int hostapd_cli_cmd_bss_tm_req(struct wpa_ctrl *ctrl, int argc,
 	}
 
 	res = os_snprintf(buf, sizeof(buf), "BSS_TM_REQ %s", argv[0]);
-	if (res < 0 || res >= (int) sizeof(buf))
+	if (os_snprintf_error(sizeof(buf), res))
 		return -1;
 
 	total = res;
@@ -736,7 +736,7 @@ static int hostapd_cli_cmd_set_qos_map_set(struct wpa_ctrl *ctrl,
 	}
 
 	res = os_snprintf(buf, sizeof(buf), "SET_QOS_MAP_SET %s", argv[0]);
-	if (res < 0 || res >= (int) sizeof(buf))
+	if (os_snprintf_error(sizeof(buf), res))
 		return -1;
 	return wpa_ctrl_command(ctrl, buf);
 }
@@ -755,7 +755,7 @@ static int hostapd_cli_cmd_send_qos_map_conf(struct wpa_ctrl *ctrl,
 	}
 
 	res = os_snprintf(buf, sizeof(buf), "SEND_QOS_MAP_CONF %s", argv[0]);
-	if (res < 0 || res >= (int) sizeof(buf))
+	if (os_snprintf_error(sizeof(buf), res))
 		return -1;
 	return wpa_ctrl_command(ctrl, buf);
 }
@@ -775,7 +775,7 @@ static int hostapd_cli_cmd_hs20_wnm_notif(struct wpa_ctrl *ctrl, int argc,
 
 	res = os_snprintf(buf, sizeof(buf), "HS20_WNM_NOTIF %s %s",
 			  argv[0], argv[1]);
-	if (res < 0 || res >= (int) sizeof(buf))
+	if (os_snprintf_error(sizeof(buf), res))
 		return -1;
 	return wpa_ctrl_command(ctrl, buf);
 }
@@ -800,7 +800,7 @@ static int hostapd_cli_cmd_hs20_deauth_req(struct wpa_ctrl *ctrl, int argc,
 		res = os_snprintf(buf, sizeof(buf),
 				  "HS20_DEAUTH_REQ %s %s %s",
 				  argv[0], argv[1], argv[2]);
-	if (res < 0 || res >= (int) sizeof(buf))
+	if (os_snprintf_error(sizeof(buf), res))
 		return -1;
 	return wpa_ctrl_command(ctrl, buf);
 }
diff --git a/src/ap/ctrl_iface_ap.c b/src/ap/ctrl_iface_ap.c
index 39edbd70f..72ed9ffbc 100644
--- a/src/ap/ctrl_iface_ap.c
+++ b/src/ap/ctrl_iface_ap.c
@@ -36,7 +36,7 @@ static int hostapd_get_sta_tx_rx(struct hostapd_data *hapd,
 			  "rx_bytes=%lu\ntx_bytes=%lu\n",
 			  data.rx_packets, data.tx_packets,
 			  data.rx_bytes, data.tx_bytes);
-	if (ret < 0 || (size_t) ret >= buflen)
+	if (os_snprintf_error(buflen, ret))
 		return 0;
 	return ret;
 }
@@ -55,7 +55,7 @@ static int hostapd_get_sta_conn_time(struct sta_info *sta,
 
 	ret = os_snprintf(buf, buflen, "connected_time=%u\n",
 			  (unsigned int) age.sec);
-	if (ret < 0 || (size_t) ret >= buflen)
+	if (os_snprintf_error(buflen, ret))
 		return 0;
 	return ret;
 }
@@ -92,7 +92,7 @@ static int hostapd_ctrl_iface_sta_mib(struct hostapd_data *hapd,
 	len = 0;
 	ret = os_snprintf(buf + len, buflen - len, MACSTR "\nflags=",
 			  MAC2STR(sta->addr));
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -104,7 +104,7 @@ static int hostapd_ctrl_iface_sta_mib(struct hostapd_data *hapd,
 	ret = os_snprintf(buf + len, buflen - len, "\naid=%d\ncapability=0x%x\n"
 			  "listen_interval=%d\nsupported_rates=",
 			  sta->aid, sta->capability, sta->listen_interval);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -112,14 +112,14 @@ static int hostapd_ctrl_iface_sta_mib(struct hostapd_data *hapd,
 		ret = os_snprintf(buf + len, buflen - len, "%02x%s",
 				  sta->supported_rates[i],
 				  i + 1 < sta->supported_rates_len ? " " : "");
-		if (ret < 0 || (size_t) ret >= buflen - len)
+		if (os_snprintf_error(buflen - len, ret))
 			return len;
 		len += ret;
 	}
 
 	ret = os_snprintf(buf + len, buflen - len, "\ntimeout_next=%s\n",
 			  timeout_next_str(sta->timeout_next));
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -164,7 +164,7 @@ int hostapd_ctrl_iface_sta(struct hostapd_data *hapd, const char *txtaddr,
 
 	if (hwaddr_aton(txtaddr, addr)) {
 		ret = os_snprintf(buf, buflen, "FAIL\n");
-		if (ret < 0 || (size_t) ret >= buflen)
+		if (os_snprintf_error(buflen, ret))
 			return 0;
 		return ret;
 	}
@@ -203,7 +203,7 @@ int hostapd_ctrl_iface_sta_next(struct hostapd_data *hapd, const char *txtaddr,
 	if (hwaddr_aton(txtaddr, addr) ||
 	    (sta = ap_get_sta(hapd, addr)) == NULL) {
 		ret = os_snprintf(buf, buflen, "FAIL\n");
-		if (ret < 0 || (size_t) ret >= buflen)
+		if (os_snprintf_error(buflen, ret))
 			return 0;
 		return ret;
 	}
@@ -422,7 +422,7 @@ int hostapd_ctrl_iface_status(struct hostapd_data *hapd, char *buf,
 			  iface->num_sta_ht40_intolerant,
 			  iface->olbc_ht,
 			  iface->ht_op_mode);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -444,7 +444,7 @@ int hostapd_ctrl_iface_status(struct hostapd_data *hapd, char *buf,
 				  iface->dfs_cac_ms / 1000,
 				  left_time);
 	}
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -463,7 +463,7 @@ int hostapd_ctrl_iface_status(struct hostapd_data *hapd, char *buf,
 			  iface->conf->vht_oper_chwidth,
 			  iface->conf->vht_oper_centr_freq_seg0_idx,
 			  iface->conf->vht_oper_centr_freq_seg1_idx);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -480,7 +480,7 @@ int hostapd_ctrl_iface_status(struct hostapd_data *hapd, char *buf,
 				  wpa_ssid_txt(bss->conf->ssid.ssid,
 					       bss->conf->ssid.ssid_len),
 				  (int) i, bss->num_sta);
-		if (ret < 0 || (size_t) ret >= buflen - len)
+		if (os_snprintf_error(buflen - len, ret))
 			return len;
 		len += ret;
 	}
diff --git a/src/ap/ieee802_1x.c b/src/ap/ieee802_1x.c
index 86e07e99c..181092547 100644
--- a/src/ap/ieee802_1x.c
+++ b/src/ap/ieee802_1x.c
@@ -2359,7 +2359,7 @@ int ieee802_1x_get_mib_sta(struct hostapd_data *hapd, struct sta_info *sta,
 			  sta->aid,
 			  EAPOL_VERSION,
 			  sm->initialize);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -2387,7 +2387,7 @@ int ieee802_1x_get_mib_sta(struct hostapd_data *hapd, struct sta_info *sta,
 			  sm->reAuthPeriod,
 			  bool_txt(sm->reAuthEnabled),
 			  bool_txt(sm->keyTxEnabled));
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -2417,7 +2417,7 @@ int ieee802_1x_get_mib_sta(struct hostapd_data *hapd, struct sta_info *sta,
 			  sm->dot1xAuthEapLengthErrorFramesRx,
 			  sm->dot1xAuthLastEapolFrameVersion,
 			  MAC2STR(sm->addr));
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -2455,7 +2455,7 @@ int ieee802_1x_get_mib_sta(struct hostapd_data *hapd, struct sta_info *sta,
 			  sm->backendOtherRequestsToSupplicant,
 			  sm->backendAuthSuccesses,
 			  sm->backendAuthFails);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -2477,7 +2477,7 @@ int ieee802_1x_get_mib_sta(struct hostapd_data *hapd, struct sta_info *sta,
 			  1 : 2,
 			  (unsigned int) diff.sec,
 			  sm->identity);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -2490,7 +2490,7 @@ int ieee802_1x_get_mib_sta(struct hostapd_data *hapd, struct sta_info *sta,
 			  name1 ? name1 : "",
 			  sm->eap_type_supp,
 			  name2 ? name2 : "");
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
diff --git a/src/ap/wpa_auth.c b/src/ap/wpa_auth.c
index 7acd7ae12..c422044ad 100644
--- a/src/ap/wpa_auth.c
+++ b/src/ap/wpa_auth.c
@@ -2970,7 +2970,7 @@ int wpa_get_mib(struct wpa_authenticator *wpa_auth, char *buf, size_t buflen)
 			  wpa_bool_txt(preauth),
 			  wpa_bool_txt(wpa_auth->conf.wpa & WPA_PROTO_RSN),
 			  wpa_bool_txt(wpa_auth->conf.rsn_preauth));
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -3020,7 +3020,7 @@ int wpa_get_mib(struct wpa_authenticator *wpa_auth, char *buf, size_t buflen)
 		RSN_SUITE_ARG(wpa_auth->dot11RSNAGroupCipherRequested),
 		wpa_auth->dot11RSNATKIPCounterMeasuresInvoked,
 		wpa_auth->dot11RSNA4WayHandshakeFailures);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -3030,7 +3030,7 @@ int wpa_get_mib(struct wpa_authenticator *wpa_auth, char *buf, size_t buflen)
 	/* Private MIB */
 	ret = os_snprintf(buf + len, buflen - len, "hostapdWPAGroupState=%d\n",
 			  wpa_auth->group->wpa_group_state);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -3072,7 +3072,7 @@ int wpa_get_mib_sta(struct wpa_state_machine *sm, char *buf, size_t buflen)
 		RSN_SUITE_ARG(pairwise),
 		sm->dot11RSNAStatsTKIPLocalMICFailures,
 		sm->dot11RSNAStatsTKIPRemoteMICFailures);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
@@ -3082,7 +3082,7 @@ int wpa_get_mib_sta(struct wpa_state_machine *sm, char *buf, size_t buflen)
 			  "hostapdWPAPTKGroupState=%d\n",
 			  sm->wpa_ptk_state,
 			  sm->wpa_ptk_group_state);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
diff --git a/src/ap/wps_hostapd.c b/src/ap/wps_hostapd.c
index 69434c8c9..9ba7aba8d 100644
--- a/src/ap/wps_hostapd.c
+++ b/src/ap/wps_hostapd.c
@@ -1583,7 +1583,7 @@ int hostapd_wps_ap_pin_set(struct hostapd_data *hapd, const char *pin,
 	int ret;
 
 	ret = os_snprintf(data.pin_txt, sizeof(data.pin_txt), "%s", pin);
-	if (ret < 0 || ret >= (int) sizeof(data.pin_txt))
+	if (os_snprintf_error(sizeof(data.pin_txt), ret))
 		return -1;
 	data.timeout = timeout;
 	return hostapd_wps_for_each(hapd, wps_ap_pin_set, &data);
diff --git a/src/common/wpa_common.c b/src/common/wpa_common.c
index 340e505fd..219f40f11 100644
--- a/src/common/wpa_common.c
+++ b/src/common/wpa_common.c
@@ -1468,56 +1468,56 @@ int wpa_write_ciphers(char *start, char *end, int ciphers, const char *delim)
 	if (ciphers & WPA_CIPHER_CCMP_256) {
 		ret = os_snprintf(pos, end - pos, "%sCCMP-256",
 				  pos == start ? "" : delim);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
 	if (ciphers & WPA_CIPHER_GCMP_256) {
 		ret = os_snprintf(pos, end - pos, "%sGCMP-256",
 				  pos == start ? "" : delim);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
 	if (ciphers & WPA_CIPHER_CCMP) {
 		ret = os_snprintf(pos, end - pos, "%sCCMP",
 				  pos == start ? "" : delim);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
 	if (ciphers & WPA_CIPHER_GCMP) {
 		ret = os_snprintf(pos, end - pos, "%sGCMP",
 				  pos == start ? "" : delim);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
 	if (ciphers & WPA_CIPHER_TKIP) {
 		ret = os_snprintf(pos, end - pos, "%sTKIP",
 				  pos == start ? "" : delim);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
 	if (ciphers & WPA_CIPHER_WEP104) {
 		ret = os_snprintf(pos, end - pos, "%sWEP104",
 				  pos == start ? "" : delim);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
 	if (ciphers & WPA_CIPHER_WEP40) {
 		ret = os_snprintf(pos, end - pos, "%sWEP40",
 				  pos == start ? "" : delim);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
 	if (ciphers & WPA_CIPHER_NONE) {
 		ret = os_snprintf(pos, end - pos, "%sNONE",
 				  pos == start ? "" : delim);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
diff --git a/src/common/wpa_ctrl.c b/src/common/wpa_ctrl.c
index 57bed0414..a486e4584 100644
--- a/src/common/wpa_ctrl.c
+++ b/src/common/wpa_ctrl.c
@@ -111,7 +111,7 @@ try_again:
 			  CONFIG_CTRL_IFACE_CLIENT_DIR "/"
 			  CONFIG_CTRL_IFACE_CLIENT_PREFIX "%d-%d",
 			  (int) getpid(), counter);
-	if (ret < 0 || (size_t) ret >= sizeof(ctrl->local.sun_path)) {
+	if (os_snprintf_error(sizeof(ctrl->local.sun_path), ret)) {
 		close(ctrl->s);
 		os_free(ctrl);
 		return NULL;
diff --git a/src/crypto/tls_openssl.c b/src/crypto/tls_openssl.c
index a23898250..1c2a5db7a 100644
--- a/src/crypto/tls_openssl.c
+++ b/src/crypto/tls_openssl.c
@@ -2868,7 +2868,7 @@ int tls_connection_set_cipher_list(void *tls_ctx, struct tls_connection *conn,
 			return -1;
 		}
 		ret = os_snprintf(pos, end - pos, ":%s", suite);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			break;
 		pos += ret;
 
diff --git a/src/drivers/driver_nl80211.c b/src/drivers/driver_nl80211.c
index c5c33c8bd..087b0ef69 100644
--- a/src/drivers/driver_nl80211.c
+++ b/src/drivers/driver_nl80211.c
@@ -5238,7 +5238,7 @@ static void dump_ifidx(struct wpa_driver_nl80211_data *drv)
 		if (!drv->if_indices[i])
 			continue;
 		res = os_snprintf(pos, end - pos, " %d", drv->if_indices[i]);
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			break;
 		pos += res;
 	}
@@ -7120,14 +7120,14 @@ static int wpa_driver_nl80211_status(void *priv, char *buf, size_t buflen)
 			  bss->added_bridge ? "added_bridge=1\n" : "",
 			  bss->in_deinit ? "in_deinit=1\n" : "",
 			  bss->if_dynamic ? "if_dynamic=1\n" : "");
-	if (res < 0 || res >= end - pos)
+	if (os_snprintf_error(end - pos, res))
 		return pos - buf;
 	pos += res;
 
 	if (bss->wdev_id_set) {
 		res = os_snprintf(pos, end - pos, "wdev_id=%llu\n",
 				  (unsigned long long) bss->wdev_id);
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return pos - buf;
 		pos += res;
 	}
@@ -7186,7 +7186,7 @@ static int wpa_driver_nl80211_status(void *priv, char *buf, size_t buflen)
 			  "ignore_next_local_disconnect=1\n" : "",
 			  drv->ignore_next_local_deauth ?
 			  "ignore_next_local_deauth=1\n" : "");
-	if (res < 0 || res >= end - pos)
+	if (os_snprintf_error(end - pos, res))
 		return pos - buf;
 	pos += res;
 
@@ -7218,7 +7218,7 @@ static int wpa_driver_nl80211_status(void *priv, char *buf, size_t buflen)
 				  drv->capa.probe_resp_offloads,
 				  drv->capa.max_acl_mac_addrs,
 				  drv->capa.num_multichan_concurrent);
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return pos - buf;
 		pos += res;
 	}
diff --git a/src/drivers/driver_wext.c b/src/drivers/driver_wext.c
index 1e531b797..561cdb344 100644
--- a/src/drivers/driver_wext.c
+++ b/src/drivers/driver_wext.c
@@ -2373,7 +2373,7 @@ static int wpa_driver_wext_status(void *priv, char *buf, size_t buflen)
 			  drv->ifindex,
 			  drv->ifname,
 			  MAC2STR(addr));
-	if (res < 0 || res >= end - pos)
+	if (os_snprintf_error(end - pos, res))
 		return pos - buf;
 	pos += res;
 
diff --git a/src/eap_peer/eap.c b/src/eap_peer/eap.c
index 6e356c0df..4b6b1eb51 100644
--- a/src/eap_peer/eap.c
+++ b/src/eap_peer/eap.c
@@ -2090,7 +2090,7 @@ int eap_sm_get_status(struct eap_sm *sm, char *buf, size_t buflen, int verbose)
 	len = os_snprintf(buf, buflen,
 			  "EAP state=%s\n",
 			  eap_sm_state_txt(sm->EAP_state));
-	if (len < 0 || (size_t) len >= buflen)
+	if (os_snprintf_error(buflen, len))
 		return 0;
 
 	if (sm->selectedMethod != EAP_TYPE_NONE) {
@@ -2109,7 +2109,7 @@ int eap_sm_get_status(struct eap_sm *sm, char *buf, size_t buflen, int verbose)
 		ret = os_snprintf(buf + len, buflen - len,
 				  "selectedMethod=%d (EAP-%s)\n",
 				  sm->selectedMethod, name);
-		if (ret < 0 || (size_t) ret >= buflen - len)
+		if (os_snprintf_error(buflen - len, ret))
 			return len;
 		len += ret;
 
@@ -2130,7 +2130,7 @@ int eap_sm_get_status(struct eap_sm *sm, char *buf, size_t buflen, int verbose)
 				  eap_sm_method_state_txt(sm->methodState),
 				  eap_sm_decision_txt(sm->decision),
 				  sm->ClientTimeout);
-		if (ret < 0 || (size_t) ret >= buflen - len)
+		if (os_snprintf_error(buflen - len, ret))
 			return len;
 		len += ret;
 	}
diff --git a/src/eap_peer/eap_fast.c b/src/eap_peer/eap_fast.c
index 0739187c1..68d7fba88 100644
--- a/src/eap_peer/eap_fast.c
+++ b/src/eap_peer/eap_fast.c
@@ -1666,7 +1666,7 @@ static int eap_fast_get_status(struct eap_sm *sm, void *priv, char *buf,
 		ret = os_snprintf(buf + len, buflen - len,
 				  "EAP-FAST Phase2 method=%s\n",
 				  data->phase2_method->name);
-		if (ret < 0 || (size_t) ret >= buflen - len)
+		if (os_snprintf_error(buflen - len, ret))
 			return len;
 		len += ret;
 	}
diff --git a/src/eap_peer/eap_fast_pac.c b/src/eap_peer/eap_fast_pac.c
index 32da82ce8..89e604ecf 100644
--- a/src/eap_peer/eap_fast_pac.c
+++ b/src/eap_peer/eap_fast_pac.c
@@ -504,28 +504,28 @@ static void eap_fast_write(char **buf, char **pos, size_t *buf_len,
 	end = *buf + *buf_len;
 
 	ret = os_snprintf(*pos, end - *pos, "%s=", field);
-	if (ret < 0 || ret >= end - *pos)
+	if (os_snprintf_error(end - *pos, ret))
 		return;
 	*pos += ret;
 	*pos += wpa_snprintf_hex(*pos, end - *pos, data, len);
 	ret = os_snprintf(*pos, end - *pos, "\n");
-	if (ret < 0 || ret >= end - *pos)
+	if (os_snprintf_error(end - *pos, ret))
 		return;
 	*pos += ret;
 
 	if (txt) {
 		ret = os_snprintf(*pos, end - *pos, "%s-txt=", field);
-		if (ret < 0 || ret >= end - *pos)
+		if (os_snprintf_error(end - *pos, ret))
 			return;
 		*pos += ret;
 		for (i = 0; i < len; i++) {
 			ret = os_snprintf(*pos, end - *pos, "%c", data[i]);
-			if (ret < 0 || ret >= end - *pos)
+			if (os_snprintf_error(end - *pos, ret))
 				return;
 			*pos += ret;
 		}
 		ret = os_snprintf(*pos, end - *pos, "\n");
-		if (ret < 0 || ret >= end - *pos)
+		if (os_snprintf_error(end - *pos, ret))
 			return;
 		*pos += ret;
 	}
@@ -578,7 +578,7 @@ static int eap_fast_add_pac_data(struct eap_fast_pac *pac, char **buf,
 
 	ret = os_snprintf(*pos, *buf + *buf_len - *pos,
 			  "START\nPAC-Type=%d\n", pac->pac_type);
-	if (ret < 0 || ret >= *buf + *buf_len - *pos)
+	if (os_snprintf_error(*buf + *buf_len - *pos, ret))
 		return -1;
 
 	*pos += ret;
@@ -600,7 +600,7 @@ static int eap_fast_add_pac_data(struct eap_fast_pac *pac, char **buf,
 		return -1;
 	}
 	ret = os_snprintf(*pos, *buf + *buf_len - *pos, "END\n");
-	if (ret < 0 || ret >= *buf + *buf_len - *pos)
+	if (os_snprintf_error(*buf + *buf_len - *pos, ret))
 		return -1;
 	*pos += ret;
 
@@ -632,7 +632,7 @@ int eap_fast_save_pac(struct eap_sm *sm, struct eap_fast_pac *pac_root,
 		return -1;
 
 	ret = os_snprintf(pos, buf + buf_len - pos, "%s\n", pac_file_hdr);
-	if (ret < 0 || ret >= buf + buf_len - pos) {
+	if (os_snprintf_error(buf + buf_len - pos, ret)) {
 		os_free(buf);
 		return -1;
 	}
diff --git a/src/eap_peer/eap_methods.c b/src/eap_peer/eap_methods.c
index 49985672b..1bdd81e1a 100644
--- a/src/eap_peer/eap_methods.c
+++ b/src/eap_peer/eap_methods.c
@@ -103,7 +103,7 @@ size_t eap_get_names(char *buf, size_t buflen)
 	for (m = eap_methods; m; m = m->next) {
 		ret = os_snprintf(pos, end - pos, "%s%s",
 				  m == eap_methods ? "" : " ", m->name);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			break;
 		pos += ret;
 	}
diff --git a/src/eap_peer/eap_peap.c b/src/eap_peer/eap_peap.c
index 472e861b0..86a18bb86 100644
--- a/src/eap_peer/eap_peap.c
+++ b/src/eap_peer/eap_peap.c
@@ -1156,7 +1156,7 @@ static int eap_peap_get_status(struct eap_sm *sm, void *priv, char *buf,
 				  "EAP-PEAPv%d Phase2 method=%s\n",
 				  data->peap_version,
 				  data->phase2_method->name);
-		if (ret < 0 || (size_t) ret >= buflen - len)
+		if (os_snprintf_error(buflen - len, ret))
 			return len;
 		len += ret;
 	}
diff --git a/src/eap_peer/eap_tls_common.c b/src/eap_peer/eap_tls_common.c
index 124177ba3..ab97966f2 100644
--- a/src/eap_peer/eap_tls_common.c
+++ b/src/eap_peer/eap_tls_common.c
@@ -793,7 +793,7 @@ int eap_peer_tls_status(struct eap_sm *sm, struct eap_ssl_data *data,
 	{
 		ret = os_snprintf(buf + len, buflen - len,
 				  "EAP TLS cipher=%s\n", name);
-		if (ret < 0 || (size_t) ret >= buflen - len)
+		if (os_snprintf_error(buflen - len, ret))
 			return len;
 		len += ret;
 	}
diff --git a/src/eap_peer/eap_ttls.c b/src/eap_peer/eap_ttls.c
index a8f4a2dde..f051e5bf0 100644
--- a/src/eap_peer/eap_ttls.c
+++ b/src/eap_peer/eap_ttls.c
@@ -1571,7 +1571,7 @@ static int eap_ttls_get_status(struct eap_sm *sm, void *priv, char *buf,
 	ret = os_snprintf(buf + len, buflen - len,
 			  "EAP-TTLSv%d Phase2 method=",
 			  data->ttls_version);
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 	switch (data->phase2_type) {
diff --git a/src/eap_server/eap_sim_db.c b/src/eap_server/eap_sim_db.c
index b29f457a1..3b689ed3e 100644
--- a/src/eap_server/eap_sim_db.c
+++ b/src/eap_server/eap_sim_db.c
@@ -927,7 +927,7 @@ int eap_sim_db_get_gsm_triplets(struct eap_sim_db_data *data,
 	os_memcpy(msg + len, imsi, imsi_len);
 	len += imsi_len;
 	ret = os_snprintf(msg + len, sizeof(msg) - len, " %d", max_chal);
-	if (ret < 0 || (size_t) ret >= sizeof(msg) - len)
+	if (os_snprintf_error(sizeof(msg) - len, ret))
 		return EAP_SIM_DB_FAILURE;
 	len += ret;
 
@@ -1455,13 +1455,13 @@ int eap_sim_db_resynchronize(struct eap_sim_db_data *data,
 		len += imsi_len;
 
 		ret = os_snprintf(msg + len, sizeof(msg) - len, " ");
-		if (ret < 0 || (size_t) ret >= sizeof(msg) - len)
+		if (os_snprintf_error(sizeof(msg) - len, ret))
 			return -1;
 		len += ret;
 		len += wpa_snprintf_hex(msg + len, sizeof(msg) - len,
 					auts, EAP_AKA_AUTS_LEN);
 		ret = os_snprintf(msg + len, sizeof(msg) - len, " ");
-		if (ret < 0 || (size_t) ret >= sizeof(msg) - len)
+		if (os_snprintf_error(sizeof(msg) - len, ret))
 			return -1;
 		len += ret;
 		len += wpa_snprintf_hex(msg + len, sizeof(msg) - len,
diff --git a/src/eapol_auth/eapol_auth_dump.c b/src/eapol_auth/eapol_auth_dump.c
index 6c6969b5c..557958286 100644
--- a/src/eapol_auth/eapol_auth_dump.c
+++ b/src/eapol_auth/eapol_auth_dump.c
@@ -130,7 +130,7 @@ int eapol_auth_dump_state(struct eapol_state_machine *sm, char *buf,
 	ret = os_snprintf(pos, end - pos, "aWhile=%d\nquietWhile=%d\n"
 			  "reAuthWhen=%d\n",
 			  sm->aWhile, sm->quietWhile, sm->reAuthWhen);
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -173,7 +173,7 @@ int eapol_auth_dump_state(struct eapol_state_machine *sm, char *buf,
 			  _SB(sm->eap_if->portEnabled),
 			  _SB(sm->portValid),
 			  _SB(sm->reAuthenticate));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -215,7 +215,7 @@ int eapol_auth_dump_state(struct eapol_state_machine *sm, char *buf,
 			  sm->authAuthReauthsWhileAuthenticated,
 			  sm->authAuthEapStartsWhileAuthenticated,
 			  sm->authAuthEapLogoffWhileAuthenticated);
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -240,7 +240,7 @@ int eapol_auth_dump_state(struct eapol_state_machine *sm, char *buf,
 			  sm->backendOtherRequestsToSupplicant,
 			  sm->backendAuthSuccesses,
 			  sm->backendAuthFails);
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -251,14 +251,14 @@ int eapol_auth_dump_state(struct eapol_state_machine *sm, char *buf,
 			  reauth_timer_state_txt(sm->reauth_timer_state),
 			  sm->reAuthPeriod,
 			  _SB(sm->reAuthEnabled));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
 	ret = os_snprintf(pos, end - pos,
 			  "auth_key_tx_state=%s\n",
 			  auth_key_tx_state_txt(sm->auth_key_tx_state));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -267,7 +267,7 @@ int eapol_auth_dump_state(struct eapol_state_machine *sm, char *buf,
 			  "rxKey=%s\n",
 			  key_rx_state_txt(sm->key_rx_state),
 			  _SB(sm->rxKey));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -280,7 +280,7 @@ int eapol_auth_dump_state(struct eapol_state_machine *sm, char *buf,
 			  ctrl_dir_txt(sm->adminControlledDirections),
 			  ctrl_dir_txt(sm->operControlledDirections),
 			  _SB(sm->operEdge));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 #undef _SB
diff --git a/src/eapol_supp/eapol_supp_sm.c b/src/eapol_supp/eapol_supp_sm.c
index 895ead679..941a26945 100644
--- a/src/eapol_supp/eapol_supp_sm.c
+++ b/src/eapol_supp/eapol_supp_sm.c
@@ -1108,7 +1108,7 @@ int eapol_sm_get_status(struct eapol_sm *sm, char *buf, size_t buflen,
 			  "suppPortStatus=%s\n",
 			  eapol_supp_pae_state(sm->SUPP_PAE_state),
 			  eapol_port_status(sm->suppPortStatus));
-	if (len < 0 || (size_t) len >= buflen)
+	if (os_snprintf_error(buflen, len))
 		return 0;
 
 	if (verbose) {
@@ -1125,7 +1125,7 @@ int eapol_sm_get_status(struct eapol_sm *sm, char *buf, size_t buflen,
 				  sm->maxStart,
 				  eapol_port_control(sm->portControl),
 				  eapol_supp_be_state(sm->SUPP_BE_state));
-		if (ret < 0 || (size_t) ret >= buflen - len)
+		if (os_snprintf_error(buflen - len, ret))
 			return len;
 		len += ret;
 	}
@@ -1179,7 +1179,7 @@ int eapol_sm_get_mib(struct eapol_sm *sm, char *buf, size_t buflen)
 			  "Authorized" : "Unauthorized",
 			  sm->SUPP_BE_state);
 
-	if (ret < 0 || (size_t) ret >= buflen)
+	if (os_snprintf_error(buflen, ret))
 		return 0;
 	len = ret;
 
@@ -1207,7 +1207,7 @@ int eapol_sm_get_mib(struct eapol_sm *sm, char *buf, size_t buflen)
 			  sm->dot1xSuppLastEapolFrameVersion,
 			  MAC2STR(sm->dot1xSuppLastEapolFrameSource));
 
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
diff --git a/src/p2p/p2p.c b/src/p2p/p2p.c
index e3fc111bb..6c6f1be67 100644
--- a/src/p2p/p2p.c
+++ b/src/p2p/p2p.c
@@ -3750,7 +3750,7 @@ int p2p_get_peer_info_txt(const struct p2p_peer_info *info,
 			  "[PD_FOR_JOIN]" : "",
 			  dev->status,
 			  dev->invitation_reqs);
-	if (res < 0 || res >= end - pos)
+	if (os_snprintf_error(end - pos, res))
 		return pos - buf;
 	pos += res;
 
@@ -3760,7 +3760,7 @@ int p2p_get_peer_info_txt(const struct p2p_peer_info *info,
 				  "ext_listen_interval=%u\n",
 				  dev->ext_listen_period,
 				  dev->ext_listen_interval);
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return pos - buf;
 		pos += res;
 	}
@@ -3770,7 +3770,7 @@ int p2p_get_peer_info_txt(const struct p2p_peer_info *info,
 				  "oper_ssid=%s\n",
 				  wpa_ssid_txt(dev->oper_ssid,
 					       dev->oper_ssid_len));
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return pos - buf;
 		pos += res;
 	}
@@ -3778,7 +3778,7 @@ int p2p_get_peer_info_txt(const struct p2p_peer_info *info,
 #ifdef CONFIG_WIFI_DISPLAY
 	if (dev->info.wfd_subelems) {
 		res = os_snprintf(pos, end - pos, "wfd_subelems=");
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return pos - buf;
 		pos += res;
 
@@ -3787,7 +3787,7 @@ int p2p_get_peer_info_txt(const struct p2p_peer_info *info,
 					wpabuf_len(dev->info.wfd_subelems));
 
 		res = os_snprintf(pos, end - pos, "\n");
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return pos - buf;
 		pos += res;
 	}
diff --git a/src/p2p/p2p_parse.c b/src/p2p/p2p_parse.c
index 92943f7da..52ba19e0a 100644
--- a/src/p2p/p2p_parse.c
+++ b/src/p2p/p2p_parse.c
@@ -607,7 +607,7 @@ static int p2p_group_info_text(const u8 *gi, size_t gi_len, char *buf,
 				  "dev=" MACSTR " iface=" MACSTR,
 				  MAC2STR(cli->p2p_device_addr),
 				  MAC2STR(cli->p2p_interface_addr));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 
@@ -618,7 +618,7 @@ static int p2p_group_info_text(const u8 *gi, size_t gi_len, char *buf,
 				  wps_dev_type_bin2str(cli->pri_dev_type,
 						       devtype,
 						       sizeof(devtype)));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 
@@ -627,7 +627,7 @@ static int p2p_group_info_text(const u8 *gi, size_t gi_len, char *buf,
 					  wps_dev_type_bin2str(
 						  &cli->sec_dev_types[s * 8],
 						  devtype, sizeof(devtype)));
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
@@ -642,7 +642,7 @@ static int p2p_group_info_text(const u8 *gi, size_t gi_len, char *buf,
 		}
 
 		ret = os_snprintf(pos, end - pos, " dev_name='%s'\n", name);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -676,7 +676,7 @@ int p2p_attr_text(struct wpabuf *data, char *buf, char *end)
 				  "p2p_dev_capab=0x%x\n"
 				  "p2p_group_capab=0x%x\n",
 				  msg.capability[0], msg.capability[1]);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -688,14 +688,14 @@ int p2p_attr_text(struct wpabuf *data, char *buf, char *end)
 				  wps_dev_type_bin2str(msg.pri_dev_type,
 						       devtype,
 						       sizeof(devtype)));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
 
 	ret = os_snprintf(pos, end - pos, "p2p_device_name=%s\n",
 			  msg.device_name);
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -703,14 +703,14 @@ int p2p_attr_text(struct wpabuf *data, char *buf, char *end)
 		ret = os_snprintf(pos, end - pos, "p2p_device_addr=" MACSTR
 				  "\n",
 				  MAC2STR(msg.p2p_device_addr));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
 
 	ret = os_snprintf(pos, end - pos, "p2p_config_methods=0x%x\n",
 			  msg.config_methods);
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
diff --git a/src/p2p/p2p_utils.c b/src/p2p/p2p_utils.c
index c0da31208..f32751d79 100644
--- a/src/p2p/p2p_utils.c
+++ b/src/p2p/p2p_utils.c
@@ -390,7 +390,7 @@ void p2p_channels_dump(struct p2p_data *p2p, const char *title,
 		const struct p2p_reg_class *c;
 		c = &chan->reg_class[i];
 		ret = os_snprintf(pos, end - pos, " %u:", c->reg_class);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			break;
 		pos += ret;
 
@@ -398,7 +398,7 @@ void p2p_channels_dump(struct p2p_data *p2p, const char *title,
 			ret = os_snprintf(pos, end - pos, "%s%u",
 					  j == 0 ? "" : ",",
 					  c->channel[j]);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				break;
 			pos += ret;
 		}
diff --git a/src/radius/radius_server.c b/src/radius/radius_server.c
index d9f2df655..b315277b0 100644
--- a/src/radius/radius_server.c
+++ b/src/radius/radius_server.c
@@ -1900,7 +1900,7 @@ int radius_server_get_mib(struct radius_server_data *data, char *buf,
 			  "radiusAuthServResetTime=0\n"
 			  "radiusAuthServConfigReset=4\n",
 			  uptime);
-	if (ret < 0 || ret >= end - pos) {
+	if (os_snprintf_error(end - pos, ret)) {
 		*pos = '\0';
 		return pos - buf;
 	}
@@ -1939,7 +1939,7 @@ int radius_server_get_mib(struct radius_server_data *data, char *buf,
 			  data->counters.malformed_acct_requests,
 			  data->counters.acct_bad_authenticators,
 			  data->counters.unknown_acct_types);
-	if (ret < 0 || ret >= end - pos) {
+	if (os_snprintf_error(end - pos, ret)) {
 		*pos = '\0';
 		return pos - buf;
 	}
@@ -1997,7 +1997,7 @@ int radius_server_get_mib(struct radius_server_data *data, char *buf,
 				  cli->counters.malformed_acct_requests,
 				  cli->counters.acct_bad_authenticators,
 				  cli->counters.unknown_acct_types);
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			*pos = '\0';
 			return pos - buf;
 		}
diff --git a/src/rsn_supp/pmksa_cache.c b/src/rsn_supp/pmksa_cache.c
index 5f2962766..8af04d0f2 100644
--- a/src/rsn_supp/pmksa_cache.c
+++ b/src/rsn_supp/pmksa_cache.c
@@ -482,7 +482,7 @@ int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
 	ret = os_snprintf(pos, buf + len - pos,
 			  "Index / AA / PMKID / expiration (in seconds) / "
 			  "opportunistic\n");
-	if (ret < 0 || ret >= buf + len - pos)
+	if (os_snprintf_error(buf + len - pos, ret))
 		return pos - buf;
 	pos += ret;
 	i = 0;
@@ -491,7 +491,7 @@ int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
 		i++;
 		ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
 				  i, MAC2STR(entry->aa));
-		if (ret < 0 || ret >= buf + len - pos)
+		if (os_snprintf_error(buf + len - pos, ret))
 			return pos - buf;
 		pos += ret;
 		pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
@@ -499,7 +499,7 @@ int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
 		ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
 				  (int) (entry->expiration - now.sec),
 				  entry->opportunistic);
-		if (ret < 0 || ret >= buf + len - pos)
+		if (os_snprintf_error(buf + len - pos, ret))
 			return pos - buf;
 		pos += ret;
 		entry = entry->next;
diff --git a/src/rsn_supp/preauth.c b/src/rsn_supp/preauth.c
index 13a6cadca..af0e1085a 100644
--- a/src/rsn_supp/preauth.c
+++ b/src/rsn_supp/preauth.c
@@ -501,7 +501,7 @@ int rsn_preauth_get_status(struct wpa_sm *sm, char *buf, size_t buflen,
 	if (sm->preauth_eapol) {
 		ret = os_snprintf(pos, end - pos, "Pre-authentication "
 				  "EAPOL state machines:\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 		res = eapol_sm_get_status(sm->preauth_eapol,
diff --git a/src/rsn_supp/wpa.c b/src/rsn_supp/wpa.c
index ba42e5e42..9caf778fa 100644
--- a/src/rsn_supp/wpa.c
+++ b/src/rsn_supp/wpa.c
@@ -2015,7 +2015,7 @@ int wpa_sm_get_mib(struct wpa_sm *sm, char *buf, size_t buflen)
 			  sm->dot11RSNAConfigPMKLifetime,
 			  sm->dot11RSNAConfigPMKReauthThreshold,
 			  sm->dot11RSNAConfigSATimeout);
-	if (ret < 0 || (size_t) ret >= buflen)
+	if (os_snprintf_error(buflen, ret))
 		return 0;
 	len = ret;
 
@@ -2484,7 +2484,7 @@ int wpa_sm_get_status(struct wpa_sm *sm, char *buf, size_t buflen,
 			  wpa_cipher_txt(sm->pairwise_cipher),
 			  wpa_cipher_txt(sm->group_cipher),
 			  wpa_key_mgmt_txt(sm->key_mgmt, sm->proto));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -2497,7 +2497,7 @@ int wpa_sm_get_status(struct wpa_sm *sm, char *buf, size_t buflen,
 			ret = os_snprintf(pos, end - pos, "pmf=%d\n",
 					  (rsn.capabilities &
 					   WPA_CAPABILITY_MFPR) ? 2 : 1);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
diff --git a/src/tls/asn1.c b/src/tls/asn1.c
index 97462facb..cec109292 100644
--- a/src/tls/asn1.c
+++ b/src/tls/asn1.c
@@ -166,7 +166,7 @@ void asn1_oid_to_str(const struct asn1_oid *oid, char *buf, size_t len)
 		ret = os_snprintf(pos, buf + len - pos,
 				  "%s%lu",
 				  i == 0 ? "" : ".", oid->oid[i]);
-		if (ret < 0 || ret >= buf + len - pos)
+		if (os_snprintf_error(buf + len - pos, ret))
 			break;
 		pos += ret;
 	}
diff --git a/src/tls/x509v3.c b/src/tls/x509v3.c
index e1e4df8de..742af328c 100644
--- a/src/tls/x509v3.c
+++ b/src/tls/x509v3.c
@@ -512,7 +512,7 @@ void x509_name_string(struct x509_name *name, char *buf, size_t len)
 		ret = os_snprintf(pos, end - pos, "%s=%s, ",
 				  x509_name_attr_str(name->attr[i].type),
 				  name->attr[i].value);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			goto done;
 		pos += ret;
 	}
@@ -527,7 +527,7 @@ void x509_name_string(struct x509_name *name, char *buf, size_t len)
 	if (name->email) {
 		ret = os_snprintf(pos, end - pos, "/emailAddress=%s",
 				  name->email);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			goto done;
 		pos += ret;
 	}
diff --git a/src/utils/common.c b/src/utils/common.c
index 64f476df4..1517a487c 100644
--- a/src/utils/common.c
+++ b/src/utils/common.c
@@ -224,7 +224,7 @@ static inline int _wpa_snprintf_hex(char *buf, size_t buf_size, const u8 *data,
 	for (i = 0; i < len; i++) {
 		ret = os_snprintf(pos, end - pos, uppercase ? "%02X" : "%02x",
 				  data[i]);
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return pos - buf;
 		}
diff --git a/src/utils/uuid.c b/src/utils/uuid.c
index 2aa4bcb5f..0f224f976 100644
--- a/src/utils/uuid.c
+++ b/src/utils/uuid.c
@@ -55,7 +55,7 @@ int uuid_bin2str(const u8 *bin, char *str, size_t max_len)
 			  bin[4], bin[5], bin[6], bin[7],
 			  bin[8], bin[9], bin[10], bin[11],
 			  bin[12], bin[13], bin[14], bin[15]);
-	if (len < 0 || (size_t) len >= max_len)
+	if (os_snprintf_error(max_len, len))
 		return -1;
 	return 0;
 }
diff --git a/src/utils/wpa_debug.c b/src/utils/wpa_debug.c
index bf0833ade..622fe9ffb 100644
--- a/src/utils/wpa_debug.c
+++ b/src/utils/wpa_debug.c
@@ -619,7 +619,7 @@ void wpa_msg(void *ctx, int level, const char *fmt, ...)
 		if (ifname) {
 			int res = os_snprintf(prefix, sizeof(prefix), "%s: ",
 					      ifname);
-			if (res < 0 || res >= (int) sizeof(prefix))
+			if (os_snprintf_error(sizeof(prefix), res))
 				prefix[0] = '\0';
 		}
 	}
diff --git a/src/wps/wps.c b/src/wps/wps.c
index b0f6887ce..2c68be8c6 100644
--- a/src/wps/wps.c
+++ b/src/wps/wps.c
@@ -560,7 +560,7 @@ int wps_attr_text(struct wpabuf *data, char *buf, char *end)
 					  "wps_state=configured\n");
 		else
 			ret = 0;
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -568,7 +568,7 @@ int wps_attr_text(struct wpabuf *data, char *buf, char *end)
 	if (attr.ap_setup_locked && *attr.ap_setup_locked) {
 		ret = os_snprintf(pos, end - pos,
 				  "wps_ap_setup_locked=1\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -576,7 +576,7 @@ int wps_attr_text(struct wpabuf *data, char *buf, char *end)
 	if (attr.selected_registrar && *attr.selected_registrar) {
 		ret = os_snprintf(pos, end - pos,
 				  "wps_selected_registrar=1\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -585,7 +585,7 @@ int wps_attr_text(struct wpabuf *data, char *buf, char *end)
 		ret = os_snprintf(pos, end - pos,
 				  "wps_device_password_id=%u\n",
 				  WPA_GET_BE16(attr.dev_password_id));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -595,7 +595,7 @@ int wps_attr_text(struct wpabuf *data, char *buf, char *end)
 				  "wps_selected_registrar_config_methods="
 				  "0x%04x\n",
 				  WPA_GET_BE16(attr.sel_reg_config_methods));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -607,7 +607,7 @@ int wps_attr_text(struct wpabuf *data, char *buf, char *end)
 				  wps_dev_type_bin2str(attr.primary_dev_type,
 						       devtype,
 						       sizeof(devtype)));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -626,7 +626,7 @@ int wps_attr_text(struct wpabuf *data, char *buf, char *end)
 		str[i] = '\0';
 		ret = os_snprintf(pos, end - pos, "wps_device_name=%s\n", str);
 		os_free(str);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -635,7 +635,7 @@ int wps_attr_text(struct wpabuf *data, char *buf, char *end)
 		ret = os_snprintf(pos, end - pos,
 				  "wps_config_methods=0x%04x\n",
 				  WPA_GET_BE16(attr.config_methods));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
diff --git a/src/wps/wps_common.c b/src/wps/wps_common.c
index a282348ee..222d48559 100644
--- a/src/wps/wps_common.c
+++ b/src/wps/wps_common.c
@@ -489,7 +489,7 @@ char * wps_dev_type_bin2str(const u8 dev_type[WPS_DEV_TYPE_LEN], char *buf,
 	ret = os_snprintf(buf, buf_len, "%u-%08X-%u",
 			  WPA_GET_BE16(dev_type), WPA_GET_BE32(&dev_type[2]),
 			  WPA_GET_BE16(&dev_type[6]));
-	if (ret < 0 || (unsigned int) ret >= buf_len)
+	if (os_snprintf_error(buf_len, ret))
 		return NULL;
 
 	return buf;
diff --git a/src/wps/wps_registrar.c b/src/wps/wps_registrar.c
index b90cc25e4..ea6ea07dd 100644
--- a/src/wps/wps_registrar.c
+++ b/src/wps/wps_registrar.c
@@ -3495,7 +3495,7 @@ int wps_registrar_get_info(struct wps_registrar *reg, const u8 *addr,
 			  d->dev.model_name ? d->dev.model_name : "",
 			  d->dev.model_number ? d->dev.model_number : "",
 			  d->dev.serial_number ? d->dev.serial_number : "");
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
diff --git a/wpa_supplicant/ap.c b/wpa_supplicant/ap.c
index f3acbc111..0e6769b67 100644
--- a/wpa_supplicant/ap.c
+++ b/wpa_supplicant/ap.c
@@ -904,7 +904,7 @@ int wpas_wps_ap_pin_set(struct wpa_supplicant *wpa_s, const char *pin,
 		return -1;
 	hapd = wpa_s->ap_iface->bss[0];
 	ret = os_snprintf(pin_txt, sizeof(pin_txt), "%s", pin);
-	if (ret < 0 || ret >= (int) sizeof(pin_txt))
+	if (os_snprintf_error(sizeof(pin_txt), ret))
 		return -1;
 	os_free(hapd->conf->ap_pin);
 	hapd->conf->ap_pin = os_strdup(pin_txt);
@@ -1058,7 +1058,7 @@ int ap_ctrl_iface_wpa_get_status(struct wpa_supplicant *wpa_s, char *buf,
 			  wpa_cipher_txt(conf->wpa_group),
 			  wpa_key_mgmt_txt(conf->wpa_key_mgmt,
 					   conf->wpa));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 	return pos - buf;
diff --git a/wpa_supplicant/bgscan_learn.c b/wpa_supplicant/bgscan_learn.c
index 6a92b7351..a320cc430 100644
--- a/wpa_supplicant/bgscan_learn.c
+++ b/wpa_supplicant/bgscan_learn.c
@@ -294,7 +294,7 @@ static void bgscan_learn_timeout(void *eloop_ctx, void *timeout_ctx)
 			int ret;
 			ret = os_snprintf(pos, msg + sizeof(msg) - pos, " %d",
 					  freqs[i]);
-			if (ret < 0 || ret >= msg + sizeof(msg) - pos)
+			if (os_snprintf_error(msg + sizeof(msg) - pos, ret))
 				break;
 			pos += ret;
 		}
diff --git a/wpa_supplicant/config.c b/wpa_supplicant/config.c
index 91550c747..786d26856 100644
--- a/wpa_supplicant/config.c
+++ b/wpa_supplicant/config.c
@@ -225,7 +225,7 @@ static char * wpa_config_write_int(const struct parse_data *data,
 	if (value == NULL)
 		return NULL;
 	res = os_snprintf(value, 20, "%d", *src);
-	if (res < 0 || res >= 20) {
+	if (os_snprintf_error(20, res)) {
 		os_free(value);
 		return NULL;
 	}
@@ -270,7 +270,7 @@ static char * wpa_config_write_bssid(const struct parse_data *data,
 	if (value == NULL)
 		return NULL;
 	res = os_snprintf(value, 20, MACSTR, MAC2STR(ssid->bssid));
-	if (res < 0 || res >= 20) {
+	if (os_snprintf_error(20, res)) {
 		os_free(value);
 		return NULL;
 	}
@@ -446,7 +446,7 @@ static char * wpa_config_write_proto(const struct parse_data *data,
 	if (ssid->proto & WPA_PROTO_WPA) {
 		ret = os_snprintf(pos, end - pos, "%sWPA",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return buf;
 		pos += ret;
 	}
@@ -454,7 +454,7 @@ static char * wpa_config_write_proto(const struct parse_data *data,
 	if (ssid->proto & WPA_PROTO_RSN) {
 		ret = os_snprintf(pos, end - pos, "%sRSN",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return buf;
 		pos += ret;
 	}
@@ -462,7 +462,7 @@ static char * wpa_config_write_proto(const struct parse_data *data,
 	if (ssid->proto & WPA_PROTO_OSEN) {
 		ret = os_snprintf(pos, end - pos, "%sOSEN",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return buf;
 		pos += ret;
 	}
@@ -576,7 +576,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_PSK) {
 		ret = os_snprintf(pos, end - pos, "%sWPA-PSK",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -586,7 +586,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_IEEE8021X) {
 		ret = os_snprintf(pos, end - pos, "%sWPA-EAP",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -596,7 +596,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_IEEE8021X_NO_WPA) {
 		ret = os_snprintf(pos, end - pos, "%sIEEE8021X",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -606,7 +606,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_NONE) {
 		ret = os_snprintf(pos, end - pos, "%sNONE",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -616,7 +616,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_WPA_NONE) {
 		ret = os_snprintf(pos, end - pos, "%sWPA-NONE",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -627,7 +627,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_FT_PSK) {
 		ret = os_snprintf(pos, end - pos, "%sFT-PSK",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -637,7 +637,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_FT_IEEE8021X) {
 		ret = os_snprintf(pos, end - pos, "%sFT-EAP",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -649,7 +649,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_PSK_SHA256) {
 		ret = os_snprintf(pos, end - pos, "%sWPA-PSK-SHA256",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -659,7 +659,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_IEEE8021X_SHA256) {
 		ret = os_snprintf(pos, end - pos, "%sWPA-EAP-SHA256",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -671,7 +671,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_WPS) {
 		ret = os_snprintf(pos, end - pos, "%sWPS",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -683,7 +683,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_SAE) {
 		ret = os_snprintf(pos, end - pos, "%sSAE",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -693,7 +693,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_FT_SAE) {
 		ret = os_snprintf(pos, end - pos, "%sFT-SAE",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -705,7 +705,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_OSEN) {
 		ret = os_snprintf(pos, end - pos, "%sOSEN",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -716,7 +716,7 @@ static char * wpa_config_write_key_mgmt(const struct parse_data *data,
 	if (ssid->key_mgmt & WPA_KEY_MGMT_IEEE8021X_SUITE_B) {
 		ret = os_snprintf(pos, end - pos, "%sWPA-EAP-SUITE-B",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -892,7 +892,7 @@ static char * wpa_config_write_auth_alg(const struct parse_data *data,
 	if (ssid->auth_alg & WPA_AUTH_ALG_OPEN) {
 		ret = os_snprintf(pos, end - pos, "%sOPEN",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -902,7 +902,7 @@ static char * wpa_config_write_auth_alg(const struct parse_data *data,
 	if (ssid->auth_alg & WPA_AUTH_ALG_SHARED) {
 		ret = os_snprintf(pos, end - pos, "%sSHARED",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -912,7 +912,7 @@ static char * wpa_config_write_auth_alg(const struct parse_data *data,
 	if (ssid->auth_alg & WPA_AUTH_ALG_LEAP) {
 		ret = os_snprintf(pos, end - pos, "%sLEAP",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -1033,7 +1033,7 @@ static char * wpa_config_write_freqs(const struct parse_data *data,
 	for (i = 0; freqs[i]; i++) {
 		ret = os_snprintf(pos, end - pos, "%s%u",
 				  i == 0 ? "" : " ", freqs[i]);
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			end[-1] = '\0';
 			return buf;
 		}
@@ -1156,7 +1156,7 @@ static char * wpa_config_write_eap(const struct parse_data *data,
 		if (name) {
 			ret = os_snprintf(pos, end - pos, "%s%s",
 					  pos == buf ? "" : " ", name);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				break;
 			pos += ret;
 		}
@@ -1433,7 +1433,7 @@ static char * wpa_config_write_go_p2p_dev_addr(const struct parse_data *data,
 	if (value == NULL)
 		return NULL;
 	res = os_snprintf(value, 20, MACSTR, MAC2STR(ssid->go_p2p_dev_addr));
-	if (res < 0 || res >= 20) {
+	if (os_snprintf_error(20, res)) {
 		os_free(value);
 		return NULL;
 	}
@@ -1518,7 +1518,7 @@ static char * wpa_config_write_p2p_client_list(const struct parse_data *data,
 		res = os_snprintf(pos, end - pos, MACSTR " ",
 				  MAC2STR(ssid->p2p_client_list +
 					  (i - 1) * ETH_ALEN));
-		if (res < 0 || res >= end - pos) {
+		if (os_snprintf_error(end - pos, res)) {
 			os_free(value);
 			return NULL;
 		}
@@ -3071,7 +3071,7 @@ char * wpa_config_get_cred_no_key(struct wpa_cred *cred, const char *var)
 			ret = os_snprintf(pos, end - pos, "%s%u",
 					  i > 0 ? "\n" : "",
 					  cred->req_conn_capab_proto[i]);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return buf;
 			pos += ret;
 
@@ -3083,7 +3083,7 @@ char * wpa_config_get_cred_no_key(struct wpa_cred *cred, const char *var)
 							  "%s%d",
 							  j > 0 ? "," : ":",
 							  ports[j]);
-					if (ret < 0 || ret >= end - pos)
+					if (os_snprintf_error(end - pos, ret))
 						return buf;
 					pos += ret;
 				}
@@ -3152,7 +3152,7 @@ char * wpa_config_get_cred_no_key(struct wpa_cred *cred, const char *var)
 		for (i = 0; i < cred->num_domain; i++) {
 			ret = os_snprintf(pos, end - pos, "%s%s",
 					  i > 0 ? "\n" : "", cred->domain[i]);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return buf;
 			pos += ret;
 		}
@@ -3217,7 +3217,7 @@ char * wpa_config_get_cred_no_key(struct wpa_cred *cred, const char *var)
 			ret = os_snprintf(pos, end - pos, "%s%s",
 					  i > 0 ? "\n" : "",
 					  wpa_ssid_txt(e->ssid, e->ssid_len));
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return buf;
 			pos += ret;
 		}
@@ -3247,7 +3247,7 @@ char * wpa_config_get_cred_no_key(struct wpa_cred *cred, const char *var)
 					  i > 0 ? "\n" : "",
 					  p->fqdn, p->exact_match, p->priority,
 					  p->country);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return buf;
 			pos += ret;
 		}
diff --git a/wpa_supplicant/config_file.c b/wpa_supplicant/config_file.c
index b10d2369f..cc632b7c7 100644
--- a/wpa_supplicant/config_file.c
+++ b/wpa_supplicant/config_file.c
@@ -608,7 +608,7 @@ static void write_wep_key(FILE *f, int idx, struct wpa_ssid *ssid)
 	int res;
 
 	res = os_snprintf(field, sizeof(field), "wep_key%d", idx);
-	if (res < 0 || (size_t) res >= sizeof(field))
+	if (os_snprintf_error(sizeof(field), res))
 		return;
 	value = wpa_config_get(ssid, field);
 	if (value) {
diff --git a/wpa_supplicant/ctrl_iface.c b/wpa_supplicant/ctrl_iface.c
index f1b1e5eb3..e95277526 100644
--- a/wpa_supplicant/ctrl_iface.c
+++ b/wpa_supplicant/ctrl_iface.c
@@ -475,7 +475,7 @@ static int wpa_supplicant_ctrl_iface_get(struct wpa_supplicant *wpa_s,
 		else
 			enabled = wpa_s->global->wifi_display;
 		res = os_snprintf(buf, buflen, "%d", enabled);
-		if (res < 0 || (unsigned int) res >= buflen)
+		if (os_snprintf_error(buflen, res))
 			return -1;
 		return res;
 #endif /* CONFIG_WIFI_DISPLAY */
@@ -813,7 +813,7 @@ static int wpa_supplicant_ctrl_iface_wps_pin(struct wpa_supplicant *wpa_s,
 		if (ret < 0)
 			return -1;
 		ret = os_snprintf(buf, buflen, "%s", pin);
-		if (ret < 0 || (size_t) ret >= buflen)
+		if (os_snprintf_error(buflen, ret))
 			return -1;
 		return ret;
 	}
@@ -825,7 +825,7 @@ static int wpa_supplicant_ctrl_iface_wps_pin(struct wpa_supplicant *wpa_s,
 done:
 	/* Return the generated PIN */
 	ret = os_snprintf(buf, buflen, "%08d", ret);
-	if (ret < 0 || (size_t) ret >= buflen)
+	if (os_snprintf_error(buflen, ret))
 		return -1;
 	return ret;
 }
@@ -862,14 +862,14 @@ static int wpa_supplicant_ctrl_iface_wps_check_pin(
 		if (!wps_pin_valid(pin_val)) {
 			wpa_printf(MSG_DEBUG, "WPS: Invalid checksum digit");
 			ret = os_snprintf(buf, buflen, "FAIL-CHECKSUM\n");
-			if (ret < 0 || (size_t) ret >= buflen)
+			if (os_snprintf_error(buflen, ret))
 				return -1;
 			return ret;
 		}
 	}
 
 	ret = os_snprintf(buf, buflen, "%s", pin);
-	if (ret < 0 || (size_t) ret >= buflen)
+	if (os_snprintf_error(buflen, ret))
 		return -1;
 
 	return ret;
@@ -1603,12 +1603,12 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 		struct wpa_ssid *ssid = wpa_s->current_ssid;
 		ret = os_snprintf(pos, end - pos, "bssid=" MACSTR "\n",
 				  MAC2STR(wpa_s->bssid));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 		ret = os_snprintf(pos, end - pos, "freq=%u\n",
 				  wpa_s->assoc_freq);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 		if (ssid) {
@@ -1626,7 +1626,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 			ret = os_snprintf(pos, end - pos, "ssid=%s\nid=%d\n",
 					  wpa_ssid_txt(_ssid, ssid_len),
 					  ssid->id);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 
@@ -1637,7 +1637,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 				ret = os_snprintf(pos, end - pos,
 						  "passphrase=%s\n",
 						  ssid->passphrase);
-				if (ret < 0 || ret >= end - pos)
+				if (os_snprintf_error(end - pos, ret))
 					return pos - buf;
 				pos += ret;
 			}
@@ -1645,7 +1645,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 				ret = os_snprintf(pos, end - pos,
 						  "id_str=%s\n",
 						  ssid->id_str);
-				if (ret < 0 || ret >= end - pos)
+				if (os_snprintf_error(end - pos, ret))
 					return pos - buf;
 				pos += ret;
 			}
@@ -1698,21 +1698,21 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 	    wpa_s->sme.sae.state == SAE_ACCEPTED) {
 		ret = os_snprintf(pos, end - pos, "sae_group=%d\n",
 				  wpa_s->sme.sae.group);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
 #endif /* CONFIG_SAE */
 	ret = os_snprintf(pos, end - pos, "wpa_state=%s\n",
 			  wpa_supplicant_state_txt(wpa_s->wpa_state));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
 	if (wpa_s->l2 &&
 	    l2_packet_get_ip_addr(wpa_s->l2, tmp, sizeof(tmp)) >= 0) {
 		ret = os_snprintf(pos, end - pos, "ip_address=%s\n", tmp);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -1721,7 +1721,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 	if (wpa_s->global->p2p) {
 		ret = os_snprintf(pos, end - pos, "p2p_device_address=" MACSTR
 				  "\n", MAC2STR(wpa_s->global->p2p_dev_addr));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -1729,7 +1729,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 
 	ret = os_snprintf(pos, end - pos, "address=" MACSTR "\n",
 			  MAC2STR(wpa_s->own_addr));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -1745,7 +1745,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 			release = rel_num + 1;
 		}
 		ret = os_snprintf(pos, end - pos, "hs20=%d\n", release);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -1764,7 +1764,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 				ret = os_snprintf(pos, end - pos,
 						  "provisioning_sp=%s\n",
 						  cred->provisioning_sp);
-				if (ret < 0 || ret >= end - pos)
+				if (os_snprintf_error(end - pos, ret))
 					return pos - buf;
 				pos += ret;
 			}
@@ -1787,7 +1787,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 			}
 			ret = os_snprintf(pos, end - pos, "home_sp=%s\n",
 					  cred->domain[i]);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 
@@ -1807,7 +1807,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 				type = "unknown";
 
 			ret = os_snprintf(pos, end - pos, "sp_type=%s\n", type);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 
@@ -1833,7 +1833,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 		char uuid_str[100];
 		uuid_bin2str(wpa_s->wps->uuid, uuid_str, sizeof(uuid_str));
 		ret = os_snprintf(pos, end - pos, "uuid=%s\n", uuid_str);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -1921,7 +1921,7 @@ static int wpa_supplicant_ctrl_iface_blacklist(struct wpa_supplicant *wpa_s,
 		while (e) {
 			ret = os_snprintf(pos, end - pos, MACSTR "\n",
 					  MAC2STR(e->bssid));
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 			e = e->next;
@@ -2011,7 +2011,7 @@ static int wpa_supplicant_ctrl_iface_log_level(struct wpa_supplicant *wpa_s,
 				  "Timestamp: %d\n",
 				  debug_level_str(wpa_debug_level),
 				  wpa_debug_timestamp);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			ret = 0;
 
 		return ret;
@@ -2054,7 +2054,7 @@ static int wpa_supplicant_ctrl_iface_list_networks(
 	end = buf + buflen;
 	ret = os_snprintf(pos, end - pos,
 			  "network id / ssid / bssid / flags\n");
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -2075,7 +2075,7 @@ static int wpa_supplicant_ctrl_iface_list_networks(
 		ret = os_snprintf(pos, end - pos, "%d\t%s",
 				  ssid->id,
 				  wpa_ssid_txt(ssid->ssid, ssid->ssid_len));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return prev - buf;
 		pos += ret;
 		if (ssid->bssid_set) {
@@ -2084,7 +2084,7 @@ static int wpa_supplicant_ctrl_iface_list_networks(
 		} else {
 			ret = os_snprintf(pos, end - pos, "\tany");
 		}
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return prev - buf;
 		pos += ret;
 		ret = os_snprintf(pos, end - pos, "\t%s%s%s%s",
@@ -2095,11 +2095,11 @@ static int wpa_supplicant_ctrl_iface_list_networks(
 				  "[TEMP-DISABLED]" : "",
 				  ssid->disabled == 2 ? "[P2P-PERSISTENT]" :
 				  "");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return prev - buf;
 		pos += ret;
 		ret = os_snprintf(pos, end - pos, "\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return prev - buf;
 		pos += ret;
 
@@ -2114,7 +2114,7 @@ static char * wpa_supplicant_cipher_txt(char *pos, char *end, int cipher)
 {
 	int ret;
 	ret = os_snprintf(pos, end - pos, "-");
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos;
 	pos += ret;
 	ret = wpa_write_ciphers(pos, end, cipher, "+");
@@ -2133,13 +2133,13 @@ static char * wpa_supplicant_ie_txt(char *pos, char *end, const char *proto,
 	int ret;
 
 	ret = os_snprintf(pos, end - pos, "[%s-", proto);
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos;
 	pos += ret;
 
 	if (wpa_parse_wpa_ie(ie, ie_len, &data) < 0) {
 		ret = os_snprintf(pos, end - pos, "?]");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 		return pos;
@@ -2149,28 +2149,28 @@ static char * wpa_supplicant_ie_txt(char *pos, char *end, const char *proto,
 	if (data.key_mgmt & WPA_KEY_MGMT_IEEE8021X) {
 		ret = os_snprintf(pos, end - pos, "%sEAP",
 				  pos == start ? "" : "+");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
 	if (data.key_mgmt & WPA_KEY_MGMT_PSK) {
 		ret = os_snprintf(pos, end - pos, "%sPSK",
 				  pos == start ? "" : "+");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
 	if (data.key_mgmt & WPA_KEY_MGMT_WPA_NONE) {
 		ret = os_snprintf(pos, end - pos, "%sNone",
 				  pos == start ? "" : "+");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
 	if (data.key_mgmt & WPA_KEY_MGMT_SAE) {
 		ret = os_snprintf(pos, end - pos, "%sSAE",
 				  pos == start ? "" : "+");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
@@ -2178,21 +2178,21 @@ static char * wpa_supplicant_ie_txt(char *pos, char *end, const char *proto,
 	if (data.key_mgmt & WPA_KEY_MGMT_FT_IEEE8021X) {
 		ret = os_snprintf(pos, end - pos, "%sFT/EAP",
 				  pos == start ? "" : "+");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
 	if (data.key_mgmt & WPA_KEY_MGMT_FT_PSK) {
 		ret = os_snprintf(pos, end - pos, "%sFT/PSK",
 				  pos == start ? "" : "+");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
 	if (data.key_mgmt & WPA_KEY_MGMT_FT_SAE) {
 		ret = os_snprintf(pos, end - pos, "%sFT/SAE",
 				  pos == start ? "" : "+");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
@@ -2201,14 +2201,14 @@ static char * wpa_supplicant_ie_txt(char *pos, char *end, const char *proto,
 	if (data.key_mgmt & WPA_KEY_MGMT_IEEE8021X_SHA256) {
 		ret = os_snprintf(pos, end - pos, "%sEAP-SHA256",
 				  pos == start ? "" : "+");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
 	if (data.key_mgmt & WPA_KEY_MGMT_PSK_SHA256) {
 		ret = os_snprintf(pos, end - pos, "%sPSK-SHA256",
 				  pos == start ? "" : "+");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
@@ -2217,7 +2217,7 @@ static char * wpa_supplicant_ie_txt(char *pos, char *end, const char *proto,
 	if (data.key_mgmt & WPA_KEY_MGMT_IEEE8021X_SUITE_B) {
 		ret = os_snprintf(pos, end - pos, "%sEAP-SUITE-B",
 				  pos == start ? "" : "+");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
@@ -2226,13 +2226,13 @@ static char * wpa_supplicant_ie_txt(char *pos, char *end, const char *proto,
 
 	if (data.capabilities & WPA_CAPABILITY_PREAUTH) {
 		ret = os_snprintf(pos, end - pos, "-preauth");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos;
 		pos += ret;
 	}
 
 	ret = os_snprintf(pos, end - pos, "]");
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos;
 	pos += ret;
 
@@ -2305,7 +2305,7 @@ static int wpa_supplicant_ctrl_iface_scan_result(
 
 	ret = os_snprintf(pos, end - pos, MACSTR "\t%d\t%d\t",
 			  MAC2STR(bss->bssid), bss->freq, bss->level);
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return -1;
 	pos += ret;
 	ie = wpa_bss_get_vendor_ie(bss, WPA_IE_VENDOR_TYPE);
@@ -2319,20 +2319,20 @@ static int wpa_supplicant_ctrl_iface_scan_result(
 	pos = wpa_supplicant_wps_ie_txt(wpa_s, pos, end, bss);
 	if (!ie && !ie2 && bss->caps & IEEE80211_CAP_PRIVACY) {
 		ret = os_snprintf(pos, end - pos, "[WEP]");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
 	if (mesh) {
 		ret = os_snprintf(pos, end - pos, "[MESH]");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
 	if (bss_is_dmg(bss)) {
 		const char *s;
 		ret = os_snprintf(pos, end - pos, "[DMG]");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 		switch (bss->caps & IEEE80211_CAP_DMG_MASK) {
@@ -2350,33 +2350,33 @@ static int wpa_supplicant_ctrl_iface_scan_result(
 			break;
 		}
 		ret = os_snprintf(pos, end - pos, "%s", s);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	} else {
 		if (bss->caps & IEEE80211_CAP_IBSS) {
 			ret = os_snprintf(pos, end - pos, "[IBSS]");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return -1;
 			pos += ret;
 		}
 		if (bss->caps & IEEE80211_CAP_ESS) {
 			ret = os_snprintf(pos, end - pos, "[ESS]");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return -1;
 			pos += ret;
 		}
 	}
 	if (p2p) {
 		ret = os_snprintf(pos, end - pos, "[P2P]");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
 #ifdef CONFIG_HS20
 	if (wpa_bss_get_vendor_ie(bss, HS20_IE_VENDOR_TYPE) && ie2) {
 		ret = os_snprintf(pos, end - pos, "[HS20]");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
@@ -2384,12 +2384,12 @@ static int wpa_supplicant_ctrl_iface_scan_result(
 
 	ret = os_snprintf(pos, end - pos, "\t%s",
 			  wpa_ssid_txt(bss->ssid, bss->ssid_len));
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return -1;
 	pos += ret;
 
 	ret = os_snprintf(pos, end - pos, "\n");
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return -1;
 	pos += ret;
 
@@ -2408,7 +2408,7 @@ static int wpa_supplicant_ctrl_iface_scan_results(
 	end = buf + buflen;
 	ret = os_snprintf(pos, end - pos, "bssid / frequency / signal level / "
 			  "flags / ssid\n");
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -2627,7 +2627,7 @@ static int wpa_supplicant_ctrl_iface_add_network(
 	wpa_config_set_network_defaults(ssid);
 
 	ret = os_snprintf(buf, buflen, "%d\n", ssid->id);
-	if (ret < 0 || (size_t) ret >= buflen)
+	if (os_snprintf_error(buflen, ret))
 		return -1;
 	return ret;
 }
@@ -2909,7 +2909,7 @@ static int wpa_supplicant_ctrl_iface_list_creds(struct wpa_supplicant *wpa_s,
 	end = buf + buflen;
 	ret = os_snprintf(pos, end - pos,
 			  "cred id / realm / username / domain / imsi\n");
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -2920,7 +2920,7 @@ static int wpa_supplicant_ctrl_iface_list_creds(struct wpa_supplicant *wpa_s,
 				  cred->username ? cred->username : "",
 				  cred->domain ? cred->domain[0] : "",
 				  cred->imsi ? cred->imsi : "");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 
@@ -2946,7 +2946,7 @@ static int wpa_supplicant_ctrl_iface_add_cred(struct wpa_supplicant *wpa_s,
 	wpa_msg(wpa_s, MSG_INFO, CRED_ADDED "%d", cred->id);
 
 	ret = os_snprintf(buf, buflen, "%d\n", cred->id);
-	if (ret < 0 || (size_t) ret >= buflen)
+	if (os_snprintf_error(buflen, ret))
 		return -1;
 	return ret;
 }
@@ -3208,7 +3208,7 @@ static int ctrl_iface_get_capability_pairwise(int res, char *strict,
 			ret = os_snprintf(pos, end - pos, "%s%s",
 					  pos == buf ? "" : " ",
 					  ciphers[i].name);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
@@ -3244,7 +3244,7 @@ static int ctrl_iface_get_capability_group(int res, char *strict,
 			ret = os_snprintf(pos, end - pos, "%s%s",
 					  pos == buf ? "" : " ",
 					  ciphers[i].name);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
@@ -3276,14 +3276,14 @@ static int ctrl_iface_get_capability_key_mgmt(int res, char *strict,
 	}
 
 	ret = os_snprintf(pos, end - pos, "NONE IEEE8021X");
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
 	if (capa->key_mgmt & (WPA_DRIVER_CAPA_KEY_MGMT_WPA |
 			      WPA_DRIVER_CAPA_KEY_MGMT_WPA2)) {
 		ret = os_snprintf(pos, end - pos, " WPA-EAP");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3291,14 +3291,14 @@ static int ctrl_iface_get_capability_key_mgmt(int res, char *strict,
 	if (capa->key_mgmt & (WPA_DRIVER_CAPA_KEY_MGMT_WPA_PSK |
 			      WPA_DRIVER_CAPA_KEY_MGMT_WPA2_PSK)) {
 		ret = os_snprintf(pos, end - pos, " WPA-PSK");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
 
 	if (capa->key_mgmt & WPA_DRIVER_CAPA_KEY_MGMT_WPA_NONE) {
 		ret = os_snprintf(pos, end - pos, " WPA-NONE");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3331,7 +3331,7 @@ static int ctrl_iface_get_capability_proto(int res, char *strict,
 			      WPA_DRIVER_CAPA_KEY_MGMT_WPA2_PSK)) {
 		ret = os_snprintf(pos, end - pos, "%sRSN",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3340,7 +3340,7 @@ static int ctrl_iface_get_capability_proto(int res, char *strict,
 			      WPA_DRIVER_CAPA_KEY_MGMT_WPA_PSK)) {
 		ret = os_snprintf(pos, end - pos, "%sWPA",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3372,7 +3372,7 @@ static int ctrl_iface_get_capability_auth_alg(int res, char *strict,
 	if (capa->auth & (WPA_DRIVER_AUTH_OPEN)) {
 		ret = os_snprintf(pos, end - pos, "%sOPEN",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3380,7 +3380,7 @@ static int ctrl_iface_get_capability_auth_alg(int res, char *strict,
 	if (capa->auth & (WPA_DRIVER_AUTH_SHARED)) {
 		ret = os_snprintf(pos, end - pos, "%sSHARED",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3388,7 +3388,7 @@ static int ctrl_iface_get_capability_auth_alg(int res, char *strict,
 	if (capa->auth & (WPA_DRIVER_AUTH_LEAP)) {
 		ret = os_snprintf(pos, end - pos, "%sLEAP",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3420,7 +3420,7 @@ static int ctrl_iface_get_capability_modes(int res, char *strict,
 	if (capa->flags & WPA_DRIVER_FLAGS_IBSS) {
 		ret = os_snprintf(pos, end - pos, "%sIBSS",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3428,7 +3428,7 @@ static int ctrl_iface_get_capability_modes(int res, char *strict,
 	if (capa->flags & WPA_DRIVER_FLAGS_AP) {
 		ret = os_snprintf(pos, end - pos, "%sAP",
 				  pos == buf ? "" : " ");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3465,7 +3465,7 @@ static int ctrl_iface_get_capability_channels(struct wpa_supplicant *wpa_s,
 			continue;
 		}
 		ret = os_snprintf(pos, end - pos, "Mode[%s] Channels:", hmode);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 		chnl = wpa_s->hw.modes[j].channels;
@@ -3473,12 +3473,12 @@ static int ctrl_iface_get_capability_channels(struct wpa_supplicant *wpa_s,
 			if (chnl[i].flag & HOSTAPD_CHAN_DISABLED)
 				continue;
 			ret = os_snprintf(pos, end - pos, " %d", chnl[i].chan);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
 		ret = os_snprintf(pos, end - pos, "\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3516,7 +3516,7 @@ static int ctrl_iface_get_capability_freq(struct wpa_supplicant *wpa_s,
 		}
 		ret = os_snprintf(pos, end - pos, "Mode[%s] Channels:\n",
 				  hmode);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 		chnl = wpa_s->hw.modes[j].channels;
@@ -3530,12 +3530,12 @@ static int ctrl_iface_get_capability_freq(struct wpa_supplicant *wpa_s,
 					  chnl[i].flag & HOSTAPD_CHAN_RADAR ?
 					  " (DFS)" : "");
 
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
 		ret = os_snprintf(pos, end - pos, "\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -3612,7 +3612,7 @@ static int wpa_supplicant_ctrl_iface_get_capability(
 #ifdef CONFIG_ERP
 	if (os_strcmp(field, "erp") == 0) {
 		res = os_snprintf(buf, buflen, "ERP");
-		if (res < 0 || (unsigned int) res >= buflen)
+		if (os_snprintf_error(buflen, res))
 			return -1;
 		return res;
 	}
@@ -3638,20 +3638,20 @@ static char * anqp_add_hex(char *pos, char *end, const char *title,
 		return start;
 
 	ret = os_snprintf(pos, end - pos, "%s=", title);
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return start;
 	pos += ret;
 
 	d = wpabuf_head_u8(data);
 	for (i = 0; i < wpabuf_len(data); i++) {
 		ret = os_snprintf(pos, end - pos, "%02x", *d++);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return start;
 		pos += ret;
 	}
 
 	ret = os_snprintf(pos, end - pos, "\n");
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return start;
 	pos += ret;
 
@@ -3673,7 +3673,7 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 
 	if (mask & WPA_BSS_MASK_ID) {
 		ret = os_snprintf(pos, end - pos, "id=%u\n", bss->id);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
@@ -3681,14 +3681,14 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 	if (mask & WPA_BSS_MASK_BSSID) {
 		ret = os_snprintf(pos, end - pos, "bssid=" MACSTR "\n",
 				  MAC2STR(bss->bssid));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
 
 	if (mask & WPA_BSS_MASK_FREQ) {
 		ret = os_snprintf(pos, end - pos, "freq=%d\n", bss->freq);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
@@ -3696,7 +3696,7 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 	if (mask & WPA_BSS_MASK_BEACON_INT) {
 		ret = os_snprintf(pos, end - pos, "beacon_int=%d\n",
 				  bss->beacon_int);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
@@ -3704,28 +3704,28 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 	if (mask & WPA_BSS_MASK_CAPABILITIES) {
 		ret = os_snprintf(pos, end - pos, "capabilities=0x%04x\n",
 				  bss->caps);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
 
 	if (mask & WPA_BSS_MASK_QUAL) {
 		ret = os_snprintf(pos, end - pos, "qual=%d\n", bss->qual);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
 
 	if (mask & WPA_BSS_MASK_NOISE) {
 		ret = os_snprintf(pos, end - pos, "noise=%d\n", bss->noise);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
 
 	if (mask & WPA_BSS_MASK_LEVEL) {
 		ret = os_snprintf(pos, end - pos, "level=%d\n", bss->level);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
@@ -3733,7 +3733,7 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 	if (mask & WPA_BSS_MASK_TSF) {
 		ret = os_snprintf(pos, end - pos, "tsf=%016llu\n",
 				  (unsigned long long) bss->tsf);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
@@ -3744,34 +3744,34 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 		os_get_reltime(&now);
 		ret = os_snprintf(pos, end - pos, "age=%d\n",
 				  (int) (now.sec - bss->last_update.sec));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
 
 	if (mask & WPA_BSS_MASK_IE) {
 		ret = os_snprintf(pos, end - pos, "ie=");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 
 		ie = (const u8 *) (bss + 1);
 		for (i = 0; i < bss->ie_len; i++) {
 			ret = os_snprintf(pos, end - pos, "%02x", *ie++);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return 0;
 			pos += ret;
 		}
 
 		ret = os_snprintf(pos, end - pos, "\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
 
 	if (mask & WPA_BSS_MASK_FLAGS) {
 		ret = os_snprintf(pos, end - pos, "flags=");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 
@@ -3786,14 +3786,14 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 		pos = wpa_supplicant_wps_ie_txt(wpa_s, pos, end, bss);
 		if (!ie && !ie2 && bss->caps & IEEE80211_CAP_PRIVACY) {
 			ret = os_snprintf(pos, end - pos, "[WEP]");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return 0;
 			pos += ret;
 		}
 		if (bss_is_dmg(bss)) {
 			const char *s;
 			ret = os_snprintf(pos, end - pos, "[DMG]");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return 0;
 			pos += ret;
 			switch (bss->caps & IEEE80211_CAP_DMG_MASK) {
@@ -3811,19 +3811,19 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 				break;
 			}
 			ret = os_snprintf(pos, end - pos, "%s", s);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return 0;
 			pos += ret;
 		} else {
 			if (bss->caps & IEEE80211_CAP_IBSS) {
 				ret = os_snprintf(pos, end - pos, "[IBSS]");
-				if (ret < 0 || ret >= end - pos)
+				if (os_snprintf_error(end - pos, ret))
 					return 0;
 				pos += ret;
 			}
 			if (bss->caps & IEEE80211_CAP_ESS) {
 				ret = os_snprintf(pos, end - pos, "[ESS]");
-				if (ret < 0 || ret >= end - pos)
+				if (os_snprintf_error(end - pos, ret))
 					return 0;
 				pos += ret;
 			}
@@ -3831,21 +3831,21 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 		if (wpa_bss_get_vendor_ie(bss, P2P_IE_VENDOR_TYPE) ||
 		    wpa_bss_get_vendor_ie_beacon(bss, P2P_IE_VENDOR_TYPE)) {
 			ret = os_snprintf(pos, end - pos, "[P2P]");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return 0;
 			pos += ret;
 		}
 #ifdef CONFIG_HS20
 		if (wpa_bss_get_vendor_ie(bss, HS20_IE_VENDOR_TYPE)) {
 			ret = os_snprintf(pos, end - pos, "[HS20]");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return 0;
 			pos += ret;
 		}
 #endif /* CONFIG_HS20 */
 
 		ret = os_snprintf(pos, end - pos, "\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
@@ -3853,7 +3853,7 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 	if (mask & WPA_BSS_MASK_SSID) {
 		ret = os_snprintf(pos, end - pos, "ssid=%s\n",
 				  wpa_ssid_txt(bss->ssid, bss->ssid_len));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
@@ -3886,7 +3886,7 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 						  WFD_IE_VENDOR_TYPE);
 		if (wfd) {
 			ret = os_snprintf(pos, end - pos, "wfd_subelems=");
-			if (ret < 0 || ret >= end - pos) {
+			if (os_snprintf_error(end - pos, ret)) {
 				wpabuf_free(wfd);
 				return 0;
 			}
@@ -3898,7 +3898,7 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 			wpabuf_free(wfd);
 
 			ret = os_snprintf(pos, end - pos, "\n");
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return 0;
 			pos += ret;
 		}
@@ -3948,7 +3948,7 @@ static int print_bss_info(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 
 	if (mask & WPA_BSS_MASK_DELIM) {
 		ret = os_snprintf(pos, end - pos, "====\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return 0;
 		pos += ret;
 	}
@@ -4358,7 +4358,7 @@ static int p2p_ctrl_connect(struct wpa_supplicant *wpa_s, char *cmd,
 		return -1;
 	if (wps_method == WPS_PIN_DISPLAY && pin == NULL) {
 		ret = os_snprintf(buf, buflen, "%08d", new_pin);
-		if (ret < 0 || (size_t) ret >= buflen)
+		if (os_snprintf_error(buflen, ret))
 			return -1;
 		return ret;
 	}
@@ -4473,7 +4473,7 @@ static int p2p_ctrl_serv_disc_req(struct wpa_supplicant *wpa_s, char *cmd,
 	if (ref == 0)
 		return -1;
 	res = os_snprintf(buf, buflen, "%llx", (long long unsigned) ref);
-	if (res < 0 || (unsigned) res >= buflen)
+	if (os_snprintf_error(buflen, res))
 		return -1;
 	return res;
 }
@@ -4909,7 +4909,7 @@ static int p2p_ctrl_peer(struct wpa_supplicant *wpa_s, char *cmd,
 			  info->dev_capab,
 			  info->group_capab,
 			  info->level);
-	if (res < 0 || res >= end - pos)
+	if (os_snprintf_error(end - pos, res))
 		return pos - buf;
 	pos += res;
 
@@ -4920,7 +4920,7 @@ static int p2p_ctrl_peer(struct wpa_supplicant *wpa_s, char *cmd,
 		res = os_snprintf(pos, end - pos, "sec_dev_type=%s\n",
 				  wps_dev_type_bin2str(t, devtype,
 						       sizeof(devtype)));
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return pos - buf;
 		pos += res;
 	}
@@ -4928,7 +4928,7 @@ static int p2p_ctrl_peer(struct wpa_supplicant *wpa_s, char *cmd,
 	ssid = wpas_p2p_get_persistent(wpa_s, info->p2p_device_addr, NULL, 0);
 	if (ssid) {
 		res = os_snprintf(pos, end - pos, "persistent=%d\n", ssid->id);
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return pos - buf;
 		pos += res;
 	}
@@ -4940,7 +4940,7 @@ static int p2p_ctrl_peer(struct wpa_supplicant *wpa_s, char *cmd,
 
 	if (info->vendor_elems) {
 		res = os_snprintf(pos, end - pos, "vendor_elems=");
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return pos - buf;
 		pos += res;
 
@@ -4949,7 +4949,7 @@ static int p2p_ctrl_peer(struct wpa_supplicant *wpa_s, char *cmd,
 					wpabuf_len(info->vendor_elems));
 
 		res = os_snprintf(pos, end - pos, "\n");
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return pos - buf;
 		pos += res;
 	}
@@ -5804,7 +5804,7 @@ static int wpa_supplicant_signal_poll(struct wpa_supplicant *wpa_s, char *buf,
 	if (si.avg_signal) {
 		ret = os_snprintf(pos, end - pos,
 				  "AVG_RSSI=%d\n", si.avg_signal);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return -1;
 		pos += ret;
 	}
@@ -6023,7 +6023,7 @@ static int wpas_ctrl_radio_work_show(struct wpa_supplicant *wpa_s,
 		ret = os_snprintf(pos, end - pos, "%s@%s:%u:%u:%ld.%06ld\n",
 				  work->type, work->wpa_s->ifname, work->freq,
 				  work->started, diff.sec, diff.usec);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			break;
 		pos += ret;
 	}
@@ -6119,7 +6119,7 @@ static int wpas_ctrl_radio_work_add(struct wpa_supplicant *wpa_s, char *cmd,
 	}
 
 	ret = os_snprintf(buf, buflen, "%u", ework->id);
-	if (ret < 0 || (size_t) ret >= buflen)
+	if (os_snprintf_error(buflen, ret))
 		return -1;
 	return ret;
 }
@@ -7690,7 +7690,7 @@ static int wpa_supplicant_global_iface_list(struct wpa_global *global,
 		res = os_snprintf(pos, end - pos, "%s\t%s\t%s\n",
 				  tmp->drv_name, tmp->ifname,
 				  tmp->desc ? tmp->desc : "");
-		if (res < 0 || res >= end - pos) {
+		if (os_snprintf_error(end - pos, res)) {
 			*pos = '\0';
 			break;
 		}
@@ -7716,7 +7716,7 @@ static int wpa_supplicant_global_iface_interfaces(struct wpa_global *global,
 
 	while (wpa_s) {
 		res = os_snprintf(pos, end - pos, "%s\n", wpa_s->ifname);
-		if (res < 0 || res >= end - pos) {
+		if (os_snprintf_error(end - pos, res)) {
 			*pos = '\0';
 			break;
 		}
@@ -7931,12 +7931,12 @@ static int wpas_global_ctrl_iface_status(struct wpa_global *global,
 				  "p2p_state=%s\n",
 				  MAC2STR(global->p2p_dev_addr),
 				  p2p_get_state_txt(global->p2p));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	} else if (global->p2p) {
 		ret = os_snprintf(pos, end - pos, "p2p_state=DISABLED\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -7945,7 +7945,7 @@ static int wpas_global_ctrl_iface_status(struct wpa_global *global,
 #ifdef CONFIG_WIFI_DISPLAY
 	ret = os_snprintf(pos, end - pos, "wifi_display=%d\n",
 			  !!global->wifi_display);
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 #endif /* CONFIG_WIFI_DISPLAY */
@@ -7954,7 +7954,7 @@ static int wpas_global_ctrl_iface_status(struct wpa_global *global,
 		ret = os_snprintf(pos, end - pos, "ifname=%s\n"
 				  "address=" MACSTR "\n",
 				  wpa_s->ifname, MAC2STR(wpa_s->own_addr));
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
diff --git a/wpa_supplicant/ctrl_iface_unix.c b/wpa_supplicant/ctrl_iface_unix.c
index 99f3e538a..2c1c6a05b 100644
--- a/wpa_supplicant/ctrl_iface_unix.c
+++ b/wpa_supplicant/ctrl_iface_unix.c
@@ -272,7 +272,7 @@ static char * wpa_supplicant_ctrl_iface_path(struct wpa_supplicant *wpa_s)
 	}
 
 	res = os_snprintf(buf, len, "%s/%s", dir, wpa_s->ifname);
-	if (res < 0 || (size_t) res >= len) {
+	if (os_snprintf_error(len, res)) {
 		os_free(pbuf);
 		os_free(buf);
 		return NULL;
@@ -671,7 +671,7 @@ static void wpa_supplicant_ctrl_iface_send(struct wpa_supplicant *wpa_s,
 		return;
 
 	res = os_snprintf(levelstr, sizeof(levelstr), "<%d>", level);
-	if (res < 0 || (size_t) res >= sizeof(levelstr))
+	if (os_snprintf_error(sizeof(levelstr), res))
 		return;
 	idx = 0;
 	if (ifname) {
diff --git a/wpa_supplicant/dbus/dbus_new_helpers.c b/wpa_supplicant/dbus/dbus_new_helpers.c
index 750522dcf..8df7ac1f8 100644
--- a/wpa_supplicant/dbus/dbus_new_helpers.c
+++ b/wpa_supplicant/dbus/dbus_new_helpers.c
@@ -136,7 +136,7 @@ static int is_signature_correct(DBusMessage *message,
 		if (arg->dir == ARG_IN) {
 			size_t blen = registered_sig + MAX_SIG_LEN - pos;
 			ret = os_snprintf(pos, blen, "%s", arg->type);
-			if (ret < 0 || (size_t) ret >= blen)
+			if (os_snprintf_error(blen, ret))
 				return 0;
 			pos += ret;
 		}
diff --git a/wpa_supplicant/eapol_test.c b/wpa_supplicant/eapol_test.c
index f2058b8a7..aa9ab50c8 100644
--- a/wpa_supplicant/eapol_test.c
+++ b/wpa_supplicant/eapol_test.c
@@ -461,7 +461,7 @@ static void eapol_test_eap_param_needed(void *ctx, enum wpa_ctrl_req_type field,
 	len = os_snprintf(buf, buflen,
 			  WPA_CTRL_REQ "%s-%d:%s needed for SSID ",
 			  field_name, ssid->id, txt);
-	if (len < 0 || (size_t) len >= buflen) {
+	if (os_snprintf_error(buflen, len)) {
 		os_free(buf);
 		return;
 	}
diff --git a/wpa_supplicant/mesh.c b/wpa_supplicant/mesh.c
index 07d47ce33..3f262fb8c 100644
--- a/wpa_supplicant/mesh.c
+++ b/wpa_supplicant/mesh.c
@@ -403,7 +403,7 @@ static int mesh_attr_text(const u8 *ies, size_t ies_len, char *buf, char *end)
 	mesh_id[elems.mesh_id_len] = '\0';
 	ret = os_snprintf(pos, end - pos, "mesh_id=%s\n", mesh_id);
 	os_free(mesh_id);
-	if (ret < 0 || ret >= end - pos)
+	if (os_snprintf_error(end - pos, ret))
 		return pos - buf;
 	pos += ret;
 
@@ -420,7 +420,7 @@ static int mesh_attr_text(const u8 *ies, size_t ies_len, char *buf, char *end)
 				  elems.mesh_config[2], elems.mesh_config[3],
 				  elems.mesh_config[4], elems.mesh_config[5],
 				  elems.mesh_config[6]);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
@@ -446,20 +446,20 @@ static int mesh_attr_text(const u8 *ies, size_t ies_len, char *buf, char *end)
 	if (bss_basic_rate_set_len > 0) {
 		ret = os_snprintf(pos, end - pos, "bss_basic_rate_set=%d",
 				  bss_basic_rate_set[0]);
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 
 		for (i = 1; i < bss_basic_rate_set_len; i++) {
 			ret = os_snprintf(pos, end - pos, " %d",
 					  bss_basic_rate_set[i]);
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
 
 		ret = os_snprintf(pos, end - pos, "\n");
-		if (ret < 0 || ret >= end - pos)
+		if (os_snprintf_error(end - pos, ret))
 			return pos - buf;
 		pos += ret;
 	}
diff --git a/wpa_supplicant/wpa_cli.c b/wpa_supplicant/wpa_cli.c
index ee65e1098..746339e04 100644
--- a/wpa_supplicant/wpa_cli.c
+++ b/wpa_supplicant/wpa_cli.c
@@ -333,7 +333,7 @@ static int wpa_cli_open_connection(const char *ifname, int attach)
 			return -1;
 		res = os_snprintf(cfile, flen, "%s/%s", ctrl_iface_dir,
 				  ifname);
-		if (res < 0 || res >= flen) {
+		if (os_snprintf_error(flen, res)) {
 			os_free(cfile);
 			return -1;
 		}
@@ -448,13 +448,13 @@ static int write_cmd(char *buf, size_t buflen, const char *cmd, int argc,
 	end = buf + buflen;
 
 	res = os_snprintf(pos, end - pos, "%s", cmd);
-	if (res < 0 || res >= end - pos)
+	if (os_snprintf_error(end - pos, res))
 		goto fail;
 	pos += res;
 
 	for (i = 0; i < argc; i++) {
 		res = os_snprintf(pos, end - pos, " %s", argv[i]);
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			goto fail;
 		pos += res;
 	}
@@ -1085,14 +1085,14 @@ static int wpa_cli_cmd_identity(struct wpa_ctrl *ctrl, int argc, char *argv[])
 	pos = cmd;
 	ret = os_snprintf(pos, end - pos, WPA_CTRL_RSP "IDENTITY-%s:%s",
 			  argv[0], argv[1]);
-	if (ret < 0 || ret >= end - pos) {
+	if (os_snprintf_error(end - pos, ret)) {
 		printf("Too long IDENTITY command.\n");
 		return -1;
 	}
 	pos += ret;
 	for (i = 2; i < argc; i++) {
 		ret = os_snprintf(pos, end - pos, " %s", argv[i]);
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			printf("Too long IDENTITY command.\n");
 			return -1;
 		}
@@ -1118,14 +1118,14 @@ static int wpa_cli_cmd_password(struct wpa_ctrl *ctrl, int argc, char *argv[])
 	pos = cmd;
 	ret = os_snprintf(pos, end - pos, WPA_CTRL_RSP "PASSWORD-%s:%s",
 			  argv[0], argv[1]);
-	if (ret < 0 || ret >= end - pos) {
+	if (os_snprintf_error(end - pos, ret)) {
 		printf("Too long PASSWORD command.\n");
 		return -1;
 	}
 	pos += ret;
 	for (i = 2; i < argc; i++) {
 		ret = os_snprintf(pos, end - pos, " %s", argv[i]);
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			printf("Too long PASSWORD command.\n");
 			return -1;
 		}
@@ -1152,14 +1152,14 @@ static int wpa_cli_cmd_new_password(struct wpa_ctrl *ctrl, int argc,
 	pos = cmd;
 	ret = os_snprintf(pos, end - pos, WPA_CTRL_RSP "NEW_PASSWORD-%s:%s",
 			  argv[0], argv[1]);
-	if (ret < 0 || ret >= end - pos) {
+	if (os_snprintf_error(end - pos, ret)) {
 		printf("Too long NEW_PASSWORD command.\n");
 		return -1;
 	}
 	pos += ret;
 	for (i = 2; i < argc; i++) {
 		ret = os_snprintf(pos, end - pos, " %s", argv[i]);
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			printf("Too long NEW_PASSWORD command.\n");
 			return -1;
 		}
@@ -1185,14 +1185,14 @@ static int wpa_cli_cmd_pin(struct wpa_ctrl *ctrl, int argc, char *argv[])
 	pos = cmd;
 	ret = os_snprintf(pos, end - pos, WPA_CTRL_RSP "PIN-%s:%s",
 			  argv[0], argv[1]);
-	if (ret < 0 || ret >= end - pos) {
+	if (os_snprintf_error(end - pos, ret)) {
 		printf("Too long PIN command.\n");
 		return -1;
 	}
 	pos += ret;
 	for (i = 2; i < argc; i++) {
 		ret = os_snprintf(pos, end - pos, " %s", argv[i]);
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			printf("Too long PIN command.\n");
 			return -1;
 		}
@@ -1217,14 +1217,14 @@ static int wpa_cli_cmd_otp(struct wpa_ctrl *ctrl, int argc, char *argv[])
 	pos = cmd;
 	ret = os_snprintf(pos, end - pos, WPA_CTRL_RSP "OTP-%s:%s",
 			  argv[0], argv[1]);
-	if (ret < 0 || ret >= end - pos) {
+	if (os_snprintf_error(end - pos, ret)) {
 		printf("Too long OTP command.\n");
 		return -1;
 	}
 	pos += ret;
 	for (i = 2; i < argc; i++) {
 		ret = os_snprintf(pos, end - pos, " %s", argv[i]);
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			printf("Too long OTP command.\n");
 			return -1;
 		}
@@ -1250,14 +1250,14 @@ static int wpa_cli_cmd_sim(struct wpa_ctrl *ctrl, int argc, char *argv[])
 	pos = cmd;
 	ret = os_snprintf(pos, end - pos, WPA_CTRL_RSP "SIM-%s:%s",
 			  argv[0], argv[1]);
-	if (ret < 0 || ret >= end - pos) {
+	if (os_snprintf_error(end - pos, ret)) {
 		printf("Too long SIM command.\n");
 		return -1;
 	}
 	pos += ret;
 	for (i = 2; i < argc; i++) {
 		ret = os_snprintf(pos, end - pos, " %s", argv[i]);
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			printf("Too long SIM command.\n");
 			return -1;
 		}
@@ -1283,14 +1283,14 @@ static int wpa_cli_cmd_passphrase(struct wpa_ctrl *ctrl, int argc,
 	pos = cmd;
 	ret = os_snprintf(pos, end - pos, WPA_CTRL_RSP "PASSPHRASE-%s:%s",
 			  argv[0], argv[1]);
-	if (ret < 0 || ret >= end - pos) {
+	if (os_snprintf_error(end - pos, ret)) {
 		printf("Too long PASSPHRASE command.\n");
 		return -1;
 	}
 	pos += ret;
 	for (i = 2; i < argc; i++) {
 		ret = os_snprintf(pos, end - pos, " %s", argv[i]);
-		if (ret < 0 || ret >= end - pos) {
+		if (os_snprintf_error(end - pos, ret)) {
 			printf("Too long PASSPHRASE command.\n");
 			return -1;
 		}
@@ -1626,7 +1626,7 @@ static int wpa_cli_cmd_interface_add(struct wpa_ctrl *ctrl, int argc,
 			  argc > 1 ? argv[1] : "", argc > 2 ? argv[2] : "",
 			  argc > 3 ? argv[3] : "", argc > 4 ? argv[4] : "",
 			  argc > 5 ? argv[5] : "");
-	if (res < 0 || (size_t) res >= sizeof(cmd))
+	if (os_snprintf_error(sizeof(cmd), res))
 		return -1;
 	cmd[sizeof(cmd) - 1] = '\0';
 	return wpa_ctrl_command(ctrl, cmd);
@@ -1933,7 +1933,7 @@ static int wpa_cli_cmd_p2p_serv_disc_resp(struct wpa_ctrl *ctrl, int argc,
 
 	res = os_snprintf(cmd, sizeof(cmd), "P2P_SERV_DISC_RESP %s %s %s %s",
 			  argv[0], argv[1], argv[2], argv[3]);
-	if (res < 0 || (size_t) res >= sizeof(cmd))
+	if (os_snprintf_error(sizeof(cmd), res))
 		return -1;
 	cmd[sizeof(cmd) - 1] = '\0';
 	return wpa_ctrl_command(ctrl, cmd);
@@ -1981,7 +1981,7 @@ static int wpa_cli_cmd_p2p_service_add(struct wpa_ctrl *ctrl, int argc,
 		res = os_snprintf(cmd, sizeof(cmd),
 				  "P2P_SERVICE_ADD %s %s %s",
 				  argv[0], argv[1], argv[2]);
-	if (res < 0 || (size_t) res >= sizeof(cmd))
+	if (os_snprintf_error(sizeof(cmd), res))
 		return -1;
 	cmd[sizeof(cmd) - 1] = '\0';
 	return wpa_ctrl_command(ctrl, cmd);
@@ -2008,7 +2008,7 @@ static int wpa_cli_cmd_p2p_service_del(struct wpa_ctrl *ctrl, int argc,
 		res = os_snprintf(cmd, sizeof(cmd),
 				  "P2P_SERVICE_DEL %s %s",
 				  argv[0], argv[1]);
-	if (res < 0 || (size_t) res >= sizeof(cmd))
+	if (os_snprintf_error(sizeof(cmd), res))
 		return -1;
 	cmd[sizeof(cmd) - 1] = '\0';
 	return wpa_ctrl_command(ctrl, cmd);
@@ -2230,7 +2230,7 @@ static int wpa_cli_cmd_wfd_subelem_set(struct wpa_ctrl *ctrl, int argc,
 
 	res = os_snprintf(cmd, sizeof(cmd), "WFD_SUBELEM_SET %s %s",
 			  argv[0], argc > 1 ? argv[1] : "");
-	if (res < 0 || (size_t) res >= sizeof(cmd))
+	if (os_snprintf_error(sizeof(cmd), res))
 		return -1;
 	cmd[sizeof(cmd) - 1] = '\0';
 	return wpa_ctrl_command(ctrl, cmd);
@@ -2251,7 +2251,7 @@ static int wpa_cli_cmd_wfd_subelem_get(struct wpa_ctrl *ctrl, int argc,
 
 	res = os_snprintf(cmd, sizeof(cmd), "WFD_SUBELEM_GET %s",
 			  argv[0]);
-	if (res < 0 || (size_t) res >= sizeof(cmd))
+	if (os_snprintf_error(sizeof(cmd), res))
 		return -1;
 	cmd[sizeof(cmd) - 1] = '\0';
 	return wpa_ctrl_command(ctrl, cmd);
diff --git a/wpa_supplicant/wpas_glue.c b/wpa_supplicant/wpas_glue.c
index 172b5f26a..3bf513528 100644
--- a/wpa_supplicant/wpas_glue.c
+++ b/wpa_supplicant/wpas_glue.c
@@ -800,7 +800,7 @@ static void wpa_supplicant_eap_param_needed(void *ctx,
 	len = os_snprintf(buf, buflen,
 			  WPA_CTRL_REQ "%s-%d:%s needed for SSID ",
 			  field_name, ssid->id, txt);
-	if (len < 0 || (size_t) len >= buflen) {
+	if (os_snprintf_error(buflen, len)) {
 		os_free(buf);
 		return;
 	}
diff --git a/wpa_supplicant/wps_supplicant.c b/wpa_supplicant/wps_supplicant.c
index 94064df0a..d8ceb5b24 100644
--- a/wpa_supplicant/wps_supplicant.c
+++ b/wpa_supplicant/wps_supplicant.c
@@ -1254,7 +1254,7 @@ int wpas_wps_start_reg(struct wpa_supplicant *wpa_s, const u8 *bssid,
 	pos = val;
 	end = pos + sizeof(val);
 	res = os_snprintf(pos, end - pos, "\"pin=%s", pin);
-	if (res < 0 || res >= end - pos)
+	if (os_snprintf_error(end - pos, res))
 		return -1;
 	pos += res;
 	if (settings) {
@@ -1262,12 +1262,12 @@ int wpas_wps_start_reg(struct wpa_supplicant *wpa_s, const u8 *bssid,
 				  "new_encr=%s new_key=%s",
 				  settings->ssid_hex, settings->auth,
 				  settings->encr, settings->key_hex);
-		if (res < 0 || res >= end - pos)
+		if (os_snprintf_error(end - pos, res))
 			return -1;
 		pos += res;
 	}
 	res = os_snprintf(pos, end - pos, "\"");
-	if (res < 0 || res >= end - pos)
+	if (os_snprintf_error(end - pos, res))
 		return -1;
 	if (wpa_config_set(ssid, "phase1", val, 0) < 0)
 		return -1;