diff --git a/lib/memdebug.c b/lib/memdebug.c
index 83cc5d30716df086e6aba1850945b6704f47c801..ba3c964c9e9449ca30627f0d6008cb5789be1534 100644
--- a/lib/memdebug.c
+++ b/lib/memdebug.c
@@ -204,7 +204,7 @@ void curl_dofree(void *ptr, int line, const char *source)
 int curl_socket(int domain, int type, int protocol, int line, char *source)
 {
   int sockfd=(socket)(domain, type, protocol);
-  if(logfile)
+  if(logfile && (sockfd!=-1))
     fprintf(logfile, "FD %s:%d socket() = %d\n",
             source, line, sockfd);
   return sockfd;