failf: skip the sprintf() if there are no consumers

Closes #1936

diff --git a/lib/sendf.c b/lib/sendf.c
index 7564cb3d095d288e9ce9ffa3f951dd2c0ce83de3..cbdb233fd36717bfe9b64077600b94ad99bf7bf1 100644 (file)
--- a/lib/sendf.c
+++ b/lib/sendf.c
@@ -241,25 +241,25 @@ void Curl_infof(struct Curl_easy *data, const char *fmt, ...)
 
 void Curl_failf(struct Curl_easy *data, const char *fmt, ...)
 {
-  va_list ap;
-  size_t len;
-  char error[CURL_ERROR_SIZE + 2];
-  va_start(ap, fmt);
-
-  vsnprintf(error, CURL_ERROR_SIZE, fmt, ap);
-  len = strlen(error);
+  if(data->set.verbose || data->set.errorbuffer) {
+    va_list ap;
+    size_t len;
+    char error[CURL_ERROR_SIZE + 2];
+    va_start(ap, fmt);
+    vsnprintf(error, CURL_ERROR_SIZE, fmt, ap);
+    len = strlen(error);
 
-  if(data->set.errorbuffer && !data->state.errorbuf) {
-    strcpy(data->set.errorbuffer, error);
-    data->state.errorbuf = TRUE; /* wrote error string */
-  }
-  if(data->set.verbose) {
-    error[len] = '\n';
-    error[++len] = '\0';
-    Curl_debug(data, CURLINFO_TEXT, error, len, NULL);
+    if(data->set.errorbuffer && !data->state.errorbuf) {
+      strcpy(data->set.errorbuffer, error);
+      data->state.errorbuf = TRUE; /* wrote error string */
+    }
+    if(data->set.verbose) {
+      error[len] = '\n';
+      error[++len] = '\0';
+      Curl_debug(data, CURLINFO_TEXT, error, len, NULL);
+    }
+    va_end(ap);
   }
-
-  va_end(ap);
 }
 
 /* Curl_sendf() sends formatted data to the server */