Added error checking for samples.

docs/examples/simplepost.c

@@ -39,7 +39,12 @@ int main(void)
        itself */
     curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, (long)strlen(postthis));
 
+    /* Perform the request, res will get the return code */
     res = curl_easy_perform(curl);
+    /* Check for errors */
+    if(res != CURLE_OK)
+      fprintf(stderr, "curl_easy_perform() failed: %s\n",
+              curl_easy_strerror(res));
 
     /* always cleanup */
     curl_easy_cleanup(curl);