diff --git a/example/direct_tcpip.c b/example/direct_tcpip.c
index c0cc68aa..fc086877 100644
--- a/example/direct_tcpip.c
+++ b/example/direct_tcpip.c
@@ -99,6 +99,18 @@ int main(int argc, char *argv[])
 
     /* Connect to SSH server */
     sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+#ifdef WIN32
+    if (sock == INVALID_SOCKET) {
+        fprintf(stderr, "failed to open socket!\n");
+        return -1;
+    }
+#else
+    if (sock == -1) {
+        perror("socket");
+        return -1;
+    }
+#endif
+
     sin.sin_family = AF_INET;
     if (INADDR_NONE == (sin.sin_addr.s_addr = inet_addr(server_ip))) {
         perror("inet_addr");
diff --git a/example/subsystem_netconf.c b/example/subsystem_netconf.c
index 624ef68c..8a3f9e8a 100644
--- a/example/subsystem_netconf.c
+++ b/example/subsystem_netconf.c
@@ -137,6 +137,18 @@ int main(int argc, char *argv[])
 
     /* Connect to SSH server */
     sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+#ifdef WIN32
+    if (sock == INVALID_SOCKET) {
+        fprintf(stderr, "failed to open socket!\n");
+        return -1;
+    }
+#else
+    if (sock == -1) {
+        perror("socket");
+        return -1;
+    }
+#endif
+
     sin.sin_family = AF_INET;
     if (INADDR_NONE == (sin.sin_addr.s_addr = inet_addr(server_ip))) {
         fprintf(stderr, "inet_addr: Invalid IP address \"%s\"\n", server_ip);
diff --git a/example/tcpip-forward.c b/example/tcpip-forward.c
index fc0bfbc1..78363758 100644
--- a/example/tcpip-forward.c
+++ b/example/tcpip-forward.c
@@ -96,6 +96,18 @@ int main(int argc, char *argv[])
 
     /* Connect to SSH server */
     sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
+#ifdef WIN32
+    if (sock == INVALID_SOCKET) {
+        fprintf(stderr, "failed to open socket!\n");
+        return -1;
+    }
+#else
+    if (sock == -1) {
+        perror("socket");
+        return -1;
+    }
+#endif
+
     sin.sin_family = AF_INET;
     if (INADDR_NONE == (sin.sin_addr.s_addr = inet_addr(server_ip))) {
         perror("inet_addr");