diff --git a/common/os_calls.c b/common/os_calls.c
index 1d3a71b1..68a6a5b0 100644
--- a/common/os_calls.c
+++ b/common/os_calls.c
@@ -471,8 +471,11 @@ g_tcp_socket(void)
         {
             option_value = 0;
             option_len = sizeof(option_value);
-            setsockopt(rv, IPPROTO_IPV6, IPV6_V6ONLY, (char*)&option_value,
-                       option_len);
+            if (setsockopt(rv, IPPROTO_IPV6, IPV6_V6ONLY, (char*)&option_value,
+                       option_len) < 0)
+            {
+                log_message(LOG_LEVEL_ERROR, "g_tcp_socket: setsockopt() failed\n");
+            }
         }
     }
 #endif
@@ -484,8 +487,11 @@ g_tcp_socket(void)
         {
             option_value = 1;
             option_len = sizeof(option_value);
-            setsockopt(rv, SOL_SOCKET, SO_REUSEADDR, (char *)&option_value,
-                       option_len);
+            if (setsockopt(rv, SOL_SOCKET, SO_REUSEADDR, (char *)&option_value,
+                       option_len) < 0)
+            {
+                log_message(LOG_LEVEL_ERROR, "g_tcp_socket: setsockopt() failed\n");
+            }
         }
     }
 
@@ -498,8 +504,11 @@ g_tcp_socket(void)
         {
             option_value = 1024 * 32;
             option_len = sizeof(option_value);
-            setsockopt(rv, SOL_SOCKET, SO_SNDBUF, (char *)&option_value,
-                       option_len);
+            if (setsockopt(rv, SOL_SOCKET, SO_SNDBUF, (char *)&option_value,
+                       option_len) < 0)
+            {
+                log_message(LOG_LEVEL_ERROR, "g_tcp_socket: setsockopt() failed\n");
+            }
         }
     }
 
@@ -785,7 +794,10 @@ g_tcp_set_non_blocking(int sck)
 #else
     i = fcntl(sck, F_GETFL);
     i = i | O_NONBLOCK;
-    fcntl(sck, F_SETFL, i);
+    if (fcntl(sck, F_SETFL, i) < 0)
+    {
+        log_message(LOG_LEVEL_ERROR, "g_tcp_set_non_blocking: fcntl() failed\n");
+    }
 #endif
     return 0;
 }
@@ -1421,7 +1433,12 @@ g_set_wait_obj(tbus obj)
         return 1;
     }
 
-    sendto(s, "sig", 4, 0, (struct sockaddr *)&sa, sa_size);
+    if (sendto(s, "sig", 4, 0, (struct sockaddr *)&sa, sa_size) < 0)
+    {
+        close(s);
+        return 1;
+    }
+
     close(s);
     return 0;
 #endif
@@ -1934,8 +1951,7 @@ g_mkdir(const char *dirname)
 #if defined(_WIN32)
     return 0;
 #else
-    mkdir(dirname, S_IRWXU);
-    return 0;
+    return mkdir(dirname, S_IRWXU);
 #endif
 }
 
diff --git a/sesman/chansrv/clipboard_file.c b/sesman/chansrv/clipboard_file.c
index 96f1b0e8..ff95b0a0 100644
--- a/sesman/chansrv/clipboard_file.c
+++ b/sesman/chansrv/clipboard_file.c
@@ -446,7 +446,13 @@ clipboard_send_file_data(int streamId, int lindex,
                    full_fn);
         return 1;
     }
-    g_file_seek(fd, nPositionLow);
+    if (g_file_seek(fd, nPositionLow) < 0)
+    {
+        log_message(LOG_LEVEL_ERROR, "clipboard_send_file_data: seek error "
+            "in file: %s\n", full_fn);
+        g_file_close(fd);
+        return 1;
+    }
     make_stream(s);
     init_stream(s, cbRequested + 64);
     size = g_file_read(fd, s->data + 12, cbRequested);
diff --git a/sesman/env.c b/sesman/env.c
index 26d1a4f7..227f6bbf 100644
--- a/sesman/env.c
+++ b/sesman/env.c
@@ -129,7 +129,11 @@ env_set_user(char *username, char *passwd_file, int display,
                 {
                     /* if no auth_file_path is set, then we go for
                        $HOME/.vnc/sesman_username_passwd */
-                    g_mkdir(".vnc");
+                    if (g_mkdir(".vnc") < 0)
+                    {
+                        log_message(LOG_LEVEL_ERROR,
+                            "env_set_user: error creating .vnc dir");
+                    }
                     g_sprintf(passwd_file, "%s/.vnc/sesman_%s_passwd", pw_dir, username);
                 }
                 else
diff --git a/sesman/sesman.c b/sesman/sesman.c
index db755a65..964bc740 100644
--- a/sesman/sesman.c
+++ b/sesman/sesman.c
@@ -308,9 +308,17 @@ main(int argc, char **argv)
         g_file_close(1);
         g_file_close(2);
 
-        g_file_open("/dev/null");
-        g_file_open("/dev/null");
-        g_file_open("/dev/null");
+        if (g_file_open("/dev/null") < 0)
+        {
+        }
+
+        if (g_file_open("/dev/null") < 0)
+        {
+        }
+
+        if (g_file_open("/dev/null") < 0)
+        {
+        }
     }
 
     /* initializing locks */
diff --git a/xrdp/xrdp.c b/xrdp/xrdp.c
index ba9d02a3..02e94d41 100644
--- a/xrdp/xrdp.c
+++ b/xrdp/xrdp.c
@@ -538,9 +538,19 @@ main(int argc, char **argv)
         g_file_close(0);
         g_file_close(1);
         g_file_close(2);
-        g_file_open("/dev/null");
-        g_file_open("/dev/null");
-        g_file_open("/dev/null");
+
+        if (g_file_open("/dev/null") < 0)
+        {
+        }
+
+        if (g_file_open("/dev/null") < 0)
+        {
+        }
+
+        if (g_file_open("/dev/null") < 0)
+        {
+        }
+
         /* end of daemonizing code */
     }
 
diff --git a/xrdp/xrdp_bitmap.c b/xrdp/xrdp_bitmap.c
index 87fb0ebc..6438f0e7 100644
--- a/xrdp/xrdp_bitmap.c
+++ b/xrdp/xrdp_bitmap.c
@@ -441,7 +441,13 @@ xrdp_bitmap_load(struct xrdp_bitmap *self, const char *filename, int *palette)
         g_file_read(fd, s->data, 4);
         in_uint32_le(s, size);
         /* read bmp header */
-        g_file_seek(fd, 14);
+        if (g_file_seek(fd, 14) < 0)
+        {
+            log_message(LOG_LEVEL_ERROR, "xrdp_bitmap_load: seek error in file %s\n",
+                filename);
+            g_file_close(fd);
+            return 1;
+        }
         init_stream(s, 8192);
         g_file_read(fd, s->data, 40); /* size better be 40 */
         in_uint32_le(s, header.size);
@@ -468,7 +474,11 @@ xrdp_bitmap_load(struct xrdp_bitmap *self, const char *filename, int *palette)
 
         if (header.bit_count == 24) /* 24 bit bitmap */
         {
-            g_file_seek(fd, 14 + header.size);
+            if (g_file_seek(fd, 14 + header.size) < 0)
+            {
+                log_message(LOG_LEVEL_ERROR, "xrdp_bitmap_load: seek error in file %s\n",
+                    filename);
+            }
             xrdp_bitmap_resize(self, header.image_width, header.image_height);
             size = header.image_width * header.image_height * 3;
             init_stream(s, size);
@@ -521,7 +531,11 @@ xrdp_bitmap_load(struct xrdp_bitmap *self, const char *filename, int *palette)
         else if (header.bit_count == 8) /* 8 bit bitmap */
         {
             /* read palette */
-            g_file_seek(fd, 14 + header.size);
+            if (g_file_seek(fd, 14 + header.size) < 0)
+            {
+                log_message(LOG_LEVEL_ERROR, "xrdp_bitmap_load: seek error in file %s\n",
+                    filename);
+            }
             init_stream(s, 8192);
             g_file_read(fd, s->data, header.clr_used * sizeof(int));
 
@@ -578,7 +592,11 @@ xrdp_bitmap_load(struct xrdp_bitmap *self, const char *filename, int *palette)
         else if (header.bit_count == 4) /* 4 bit bitmap */
         {
             /* read palette */
-            g_file_seek(fd, 14 + header.size);
+            if (g_file_seek(fd, 14 + header.size) < 0)
+            {
+                log_message(LOG_LEVEL_ERROR, "xrdp_bitmap_load: seek error in file %s\n",
+                    filename);
+            }
             init_stream(s, 8192);
             g_file_read(fd, s->data, header.clr_used * sizeof(int));
 
diff --git a/xrdpapi/xrdpapi.c b/xrdpapi/xrdpapi.c
index 4cf8db71..23630804 100644
--- a/xrdpapi/xrdpapi.c
+++ b/xrdpapi/xrdpapi.c
@@ -129,7 +129,10 @@ WTSVirtualChannelOpenEx(unsigned int SessionId, const char *pVirtualName,
     /* set non blocking */
     llong = fcntl(wts->fd, F_GETFL);
     llong = llong | O_NONBLOCK;
-    fcntl(wts->fd, F_SETFL, llong);
+    if (fcntl(wts->fd, F_SETFL, llong) < 0)
+    {
+        LLOGLN(10, ("WTSVirtualChannelOpenEx: set non-block mode failed"));
+    }
 
     /* connect to chansrv session */
     memset(&s, 0, sizeof(struct sockaddr_un));