diff --git a/mongoose.c b/mongoose.c
index fa15b329..2c28431e 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -3322,7 +3322,7 @@ static void mg_set_non_blocking_mode(SOCKET fd) {
 
 bool mg_open_listener(struct mg_connection *c, const char *url) {
   SOCKET fd = INVALID_SOCKET;
-  int s_err = 0;  // Memoized socket error, in case closesocket() overrides it
+  bool success = false;
   c->loc.port = mg_htons(mg_url_port(url));
   if (!mg_aton(mg_url_host(url), &c->loc)) {
     MG_ERROR(("invalid listening URL: %s", url));
@@ -3334,47 +3334,47 @@ bool mg_open_listener(struct mg_connection *c, const char *url) {
     int proto = type == SOCK_DGRAM ? IPPROTO_UDP : IPPROTO_TCP;
     (void) on;
 
-    if ((fd = socket(af, type, proto)) != INVALID_SOCKET &&
+    if ((fd = socket(af, type, proto)) == INVALID_SOCKET) {
+      MG_ERROR(("socket: %s", MG_SOCK_ERRNO));
 #if (MG_ARCH != MG_ARCH_WIN32 || !defined(SO_EXCLUSIVEADDRUSE)) && \
     (!defined(LWIP_SOCKET) || (defined(LWIP_SOCKET) && SO_REUSE == 1))
-        // 1. SO_RESUSEADDR is not enabled on Windows because the semantics of
-        //    SO_REUSEADDR on UNIX and Windows is different. On Windows,
-        //    SO_REUSEADDR allows to bind a socket to a port without error even
-        //    if the port is already open by another program. This is not the
-        //    behavior SO_REUSEADDR was designed for, and leads to hard-to-track
-        //    failure scenarios. Therefore, SO_REUSEADDR was disabled on Windows
-        //    unless SO_EXCLUSIVEADDRUSE is supported and set on a socket.
-        // 2. In case of LWIP, SO_REUSEADDR should be explicitly enabled, by
-        // defining
-        //    SO_REUSE (in lwipopts.h), otherwise the code below will compile
-        //    but won't work! (setsockopt will return EINVAL)
-        !setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &on, sizeof(on)) &&
+    } else if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &on,
+                          sizeof(on)) != 0) {
+      // 1. SO_RESUSEADDR is not enabled on Windows because the semantics of
+      //    SO_REUSEADDR on UNIX and Windows is different. On Windows,
+      //    SO_REUSEADDR allows to bind a socket to a port without error even
+      //    if the port is already open by another program. This is not the
+      //    behavior SO_REUSEADDR was designed for, and leads to hard-to-track
+      //    failure scenarios. Therefore, SO_REUSEADDR was disabled on Windows
+      //    unless SO_EXCLUSIVEADDRUSE is supported and set on a socket.
+      // 2. In case of LWIP, SO_REUSEADDR should be explicitly enabled, by
+      // defining
+      //    SO_REUSE (in lwipopts.h), otherwise the code below will compile
+      //    but won't work! (setsockopt will return EINVAL)
+      MG_ERROR(("reuseaddr: %s", MG_SOCK_ERRNO));
 #endif
 #if MG_ARCH == MG_ARCH_WIN32 && defined(SO_EXCLUSIVEADDRUSE) && !defined(WINCE)
-        // "Using SO_REUSEADDR and SO_EXCLUSIVEADDRUSE"
-        //! setsockopt(fd, SOL_SOCKET, SO_BROADCAST, (char *) &on, sizeof(on))
-        //! &&
-        !setsockopt(fd, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (char *) &on,
-                    sizeof(on)) &&
+    } else if (setsockopt(fd, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (char *) &on,
+                          sizeof(on)) != 0) {
+      // "Using SO_REUSEADDR and SO_EXCLUSIVEADDRUSE"
+      MG_ERROR(("exclusiveaddruse: %s", MG_SOCK_ERRNO));
 #endif
-        bind(fd, &usa.sa, slen) == 0 &&
-        // NOTE(lsm): FreeRTOS uses backlog value as a connection limit
-        (type == SOCK_DGRAM || listen(fd, MG_SOCK_LISTEN_BACKLOG_SIZE) == 0)) {
+    } else if (bind(fd, &usa.sa, slen) != 0) {
+      MG_ERROR(("bind: %s", MG_SOCK_ERRNO));
+    } else if ((type == SOCK_STREAM &&
+                listen(fd, MG_SOCK_LISTEN_BACKLOG_SIZE) != 0)) {
+      // NOTE(lsm): FreeRTOS uses backlog value as a connection limit
       // In case port was set to 0, get the real port number
+      MG_ERROR(("listen: %s", MG_SOCK_ERRNO));
+    } else {
       setlocaddr(fd, &c->loc);
       mg_set_non_blocking_mode(fd);
-    } else if (fd != INVALID_SOCKET) {
-      s_err = MG_SOCK_ERRNO;
-      closesocket(fd);
-      fd = INVALID_SOCKET;
+      c->fd = S2PTR(fd);
+      success = true;
     }
   }
-  c->fd = S2PTR(fd);
-  if (fd == INVALID_SOCKET) {
-    if (s_err == 0) s_err = MG_SOCK_ERRNO;
-    MG_ERROR(("failed %s, errno %d (%s)", url, s_err, strerror(s_err)));
-  }
-  return fd != INVALID_SOCKET;
+  if (success == false && fd != INVALID_SOCKET) closesocket(fd);
+  return success;
 }
 
 static long mg_sock_recv(struct mg_connection *c, void *buf, size_t len) {
@@ -3512,8 +3512,8 @@ static void accept_conn(struct mg_mgr *mgr, struct mg_connection *lsn) {
   if (fd == INVALID_SOCKET) {
 #if MG_ARCH == MG_ARCH_AZURERTOS
     // AzureRTOS, in non-block socket mode can mark listening socket readable
-    // even it is not. See comment for 'select' func implementation in nx_bsd.c
-    // That's not an error, just should try later
+    // even it is not. See comment for 'select' func implementation in
+    // nx_bsd.c That's not an error, just should try later
     if (MG_SOCK_ERRNO != EAGAIN)
 #endif
       MG_ERROR(("%lu accept failed, errno %d", lsn->id, MG_SOCK_ERRNO));
diff --git a/src/sock.c b/src/sock.c
index 28e1590b..7bfd031f 100644
--- a/src/sock.c
+++ b/src/sock.c
@@ -185,7 +185,7 @@ static void mg_set_non_blocking_mode(SOCKET fd) {
 
 bool mg_open_listener(struct mg_connection *c, const char *url) {
   SOCKET fd = INVALID_SOCKET;
-  int s_err = 0;  // Memoized socket error, in case closesocket() overrides it
+  bool success = false;
   c->loc.port = mg_htons(mg_url_port(url));
   if (!mg_aton(mg_url_host(url), &c->loc)) {
     MG_ERROR(("invalid listening URL: %s", url));
@@ -197,47 +197,47 @@ bool mg_open_listener(struct mg_connection *c, const char *url) {
     int proto = type == SOCK_DGRAM ? IPPROTO_UDP : IPPROTO_TCP;
     (void) on;
 
-    if ((fd = socket(af, type, proto)) != INVALID_SOCKET &&
+    if ((fd = socket(af, type, proto)) == INVALID_SOCKET) {
+      MG_ERROR(("socket: %s", MG_SOCK_ERRNO));
 #if (MG_ARCH != MG_ARCH_WIN32 || !defined(SO_EXCLUSIVEADDRUSE)) && \
     (!defined(LWIP_SOCKET) || (defined(LWIP_SOCKET) && SO_REUSE == 1))
-        // 1. SO_RESUSEADDR is not enabled on Windows because the semantics of
-        //    SO_REUSEADDR on UNIX and Windows is different. On Windows,
-        //    SO_REUSEADDR allows to bind a socket to a port without error even
-        //    if the port is already open by another program. This is not the
-        //    behavior SO_REUSEADDR was designed for, and leads to hard-to-track
-        //    failure scenarios. Therefore, SO_REUSEADDR was disabled on Windows
-        //    unless SO_EXCLUSIVEADDRUSE is supported and set on a socket.
-        // 2. In case of LWIP, SO_REUSEADDR should be explicitly enabled, by
-        // defining
-        //    SO_REUSE (in lwipopts.h), otherwise the code below will compile
-        //    but won't work! (setsockopt will return EINVAL)
-        !setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &on, sizeof(on)) &&
+    } else if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &on,
+                          sizeof(on)) != 0) {
+      // 1. SO_RESUSEADDR is not enabled on Windows because the semantics of
+      //    SO_REUSEADDR on UNIX and Windows is different. On Windows,
+      //    SO_REUSEADDR allows to bind a socket to a port without error even
+      //    if the port is already open by another program. This is not the
+      //    behavior SO_REUSEADDR was designed for, and leads to hard-to-track
+      //    failure scenarios. Therefore, SO_REUSEADDR was disabled on Windows
+      //    unless SO_EXCLUSIVEADDRUSE is supported and set on a socket.
+      // 2. In case of LWIP, SO_REUSEADDR should be explicitly enabled, by
+      // defining
+      //    SO_REUSE (in lwipopts.h), otherwise the code below will compile
+      //    but won't work! (setsockopt will return EINVAL)
+      MG_ERROR(("reuseaddr: %s", MG_SOCK_ERRNO));
 #endif
 #if MG_ARCH == MG_ARCH_WIN32 && defined(SO_EXCLUSIVEADDRUSE) && !defined(WINCE)
-        // "Using SO_REUSEADDR and SO_EXCLUSIVEADDRUSE"
-        //! setsockopt(fd, SOL_SOCKET, SO_BROADCAST, (char *) &on, sizeof(on))
-        //! &&
-        !setsockopt(fd, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (char *) &on,
-                    sizeof(on)) &&
+    } else if (setsockopt(fd, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (char *) &on,
+                          sizeof(on)) != 0) {
+      // "Using SO_REUSEADDR and SO_EXCLUSIVEADDRUSE"
+      MG_ERROR(("exclusiveaddruse: %s", MG_SOCK_ERRNO));
 #endif
-        bind(fd, &usa.sa, slen) == 0 &&
-        // NOTE(lsm): FreeRTOS uses backlog value as a connection limit
-        (type == SOCK_DGRAM || listen(fd, MG_SOCK_LISTEN_BACKLOG_SIZE) == 0)) {
+    } else if (bind(fd, &usa.sa, slen) != 0) {
+      MG_ERROR(("bind: %s", MG_SOCK_ERRNO));
+    } else if ((type == SOCK_STREAM &&
+                listen(fd, MG_SOCK_LISTEN_BACKLOG_SIZE) != 0)) {
+      // NOTE(lsm): FreeRTOS uses backlog value as a connection limit
       // In case port was set to 0, get the real port number
+      MG_ERROR(("listen: %s", MG_SOCK_ERRNO));
+    } else {
       setlocaddr(fd, &c->loc);
       mg_set_non_blocking_mode(fd);
-    } else if (fd != INVALID_SOCKET) {
-      s_err = MG_SOCK_ERRNO;
-      closesocket(fd);
-      fd = INVALID_SOCKET;
+      c->fd = S2PTR(fd);
+      success = true;
     }
   }
-  c->fd = S2PTR(fd);
-  if (fd == INVALID_SOCKET) {
-    if (s_err == 0) s_err = MG_SOCK_ERRNO;
-    MG_ERROR(("failed %s, errno %d (%s)", url, s_err, strerror(s_err)));
-  }
-  return fd != INVALID_SOCKET;
+  if (success == false && fd != INVALID_SOCKET) closesocket(fd);
+  return success;
 }
 
 static long mg_sock_recv(struct mg_connection *c, void *buf, size_t len) {
@@ -375,8 +375,8 @@ static void accept_conn(struct mg_mgr *mgr, struct mg_connection *lsn) {
   if (fd == INVALID_SOCKET) {
 #if MG_ARCH == MG_ARCH_AZURERTOS
     // AzureRTOS, in non-block socket mode can mark listening socket readable
-    // even it is not. See comment for 'select' func implementation in nx_bsd.c
-    // That's not an error, just should try later
+    // even it is not. See comment for 'select' func implementation in
+    // nx_bsd.c That's not an error, just should try later
     if (MG_SOCK_ERRNO != EAGAIN)
 #endif
       MG_ERROR(("%lu accept failed, errno %d", lsn->id, MG_SOCK_ERRNO));