diff --git a/src/common/wpa_ctrl.c b/src/common/wpa_ctrl.c
index a486e4584..ccaaf1b05 100644
--- a/src/common/wpa_ctrl.c
+++ b/src/common/wpa_ctrl.c
@@ -641,7 +641,7 @@ struct wpa_ctrl * wpa_ctrl_open(const char *ctrl_path)
 		ret = os_snprintf(name, 256, NAMED_PIPE_PREFIX "-%s",
 				  ctrl_path);
 #endif /* UNICODE */
-	if (ret < 0 || ret >= 256) {
+	if (os_snprintf_error(256, ret)) {
 		os_free(ctrl);
 		return NULL;
 	}
diff --git a/src/eap_peer/eap_ttls.c b/src/eap_peer/eap_ttls.c
index f051e5bf0..6fbc27b71 100644
--- a/src/eap_peer/eap_ttls.c
+++ b/src/eap_peer/eap_ttls.c
@@ -1596,7 +1596,7 @@ static int eap_ttls_get_status(struct eap_sm *sm, void *priv, char *buf,
 		ret = 0;
 		break;
 	}
-	if (ret < 0 || (size_t) ret >= buflen - len)
+	if (os_snprintf_error(buflen - len, ret))
 		return len;
 	len += ret;
 
diff --git a/src/eap_server/eap_sim_db.c b/src/eap_server/eap_sim_db.c
index 3b689ed3e..acf543530 100644
--- a/src/eap_server/eap_sim_db.c
+++ b/src/eap_server/eap_sim_db.c
@@ -922,7 +922,8 @@ int eap_sim_db_get_gsm_triplets(struct eap_sim_db_data *data,
 
 	imsi_len = os_strlen(imsi);
 	len = os_snprintf(msg, sizeof(msg), "SIM-REQ-AUTH ");
-	if (len < 0 || len + imsi_len >= sizeof(msg))
+	if (os_snprintf_error(sizeof(msg), len) ||
+	    len + imsi_len >= sizeof(msg))
 		return EAP_SIM_DB_FAILURE;
 	os_memcpy(msg + len, imsi, imsi_len);
 	len += imsi_len;
@@ -1385,7 +1386,8 @@ int eap_sim_db_get_aka_auth(struct eap_sim_db_data *data, const char *username,
 
 	imsi_len = os_strlen(imsi);
 	len = os_snprintf(msg, sizeof(msg), "AKA-REQ-AUTH ");
-	if (len < 0 || len + imsi_len >= sizeof(msg))
+	if (os_snprintf_error(sizeof(msg), len) ||
+	    len + imsi_len >= sizeof(msg))
 		return EAP_SIM_DB_FAILURE;
 	os_memcpy(msg + len, imsi, imsi_len);
 	len += imsi_len;
@@ -1449,7 +1451,8 @@ int eap_sim_db_resynchronize(struct eap_sim_db_data *data,
 
 		imsi_len = os_strlen(imsi);
 		len = os_snprintf(msg, sizeof(msg), "AKA-AUTS ");
-		if (len < 0 || len + imsi_len >= sizeof(msg))
+		if (os_snprintf_error(sizeof(msg), len) ||
+		    len + imsi_len >= sizeof(msg))
 			return -1;
 		os_memcpy(msg + len, imsi, imsi_len);
 		len += imsi_len;
diff --git a/src/rsn_supp/wpa.c b/src/rsn_supp/wpa.c
index 9caf778fa..7c2761cc6 100644
--- a/src/rsn_supp/wpa.c
+++ b/src/rsn_supp/wpa.c
@@ -2042,7 +2042,7 @@ int wpa_sm_get_mib(struct wpa_sm *sm, char *buf, size_t buflen)
 		RSN_SUITE_ARG(wpa_cipher_to_suite(sm->proto,
 						  sm->group_cipher)),
 		sm->dot11RSNA4WayHandshakeFailures);
-	if (ret >= 0 && (size_t) ret < buflen)
+	if (!os_snprintf_error(buflen - len, ret))
 		len += ret;
 
 	return (int) len;
diff --git a/wpa_supplicant/ctrl_iface.c b/wpa_supplicant/ctrl_iface.c
index c96052b66..ae658976e 100644
--- a/wpa_supplicant/ctrl_iface.c
+++ b/wpa_supplicant/ctrl_iface.c
@@ -475,9 +475,6 @@ 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 (os_snprintf_error(buflen, res))
-			return -1;
-		return res;
 #endif /* CONFIG_WIFI_DISPLAY */
 #ifdef CONFIG_TESTING_GET_GTK
 	} else if (os_strcmp(cmd, "gtk") == 0) {
@@ -489,7 +486,7 @@ static int wpa_supplicant_ctrl_iface_get(struct wpa_supplicant *wpa_s,
 #endif /* CONFIG_TESTING_GET_GTK */
 	}
 
-	if (res < 0 || (unsigned int) res >= buflen)
+	if (os_snprintf_error(buflen, res))
 		return -1;
 	return res;
 }
@@ -1676,7 +1673,7 @@ static int wpa_supplicant_ctrl_iface_status(struct wpa_supplicant *wpa_s,
 				ret = 0;
 				break;
 			}
-			if (ret < 0 || ret >= end - pos)
+			if (os_snprintf_error(end - pos, ret))
 				return pos - buf;
 			pos += ret;
 		}
diff --git a/wpa_supplicant/dbus/dbus_new_handlers.c b/wpa_supplicant/dbus/dbus_new_handlers.c
index 6cf95d260..d6933cdb3 100644
--- a/wpa_supplicant/dbus/dbus_new_handlers.c
+++ b/wpa_supplicant/dbus/dbus_new_handlers.c
@@ -233,7 +233,7 @@ dbus_bool_t set_network_properties(struct wpa_supplicant *wpa_s,
 
 				ret = os_snprintf(value, size, "\"%s\"",
 						  entry.str_value);
-				if (ret < 0 || (size_t) ret != (size - 1))
+				if (os_snprintf_error(size, ret))
 					goto error;
 			} else {
 				value = os_strdup(entry.str_value);
diff --git a/wpa_supplicant/dbus/dbus_old_handlers.c b/wpa_supplicant/dbus/dbus_old_handlers.c
index 5f54cf141..b78644bab 100644
--- a/wpa_supplicant/dbus/dbus_old_handlers.c
+++ b/wpa_supplicant/dbus/dbus_old_handlers.c
@@ -968,7 +968,7 @@ DBusMessage * wpas_dbus_iface_set_network(DBusMessage *message,
 					goto error;
 				ret = os_snprintf(value, size, "\"%s\"",
 						  entry.str_value);
-				if (ret < 0 || (size_t) ret != (size - 1))
+				if (os_snprintf_error(size, ret))
 					goto error;
 			} else {
 				value = os_strdup(entry.str_value);