curl / libcurl / API / curl_easy_setopt / CURLOPT_DEBUGDATA

CURLOPT_DEBUGDATA explained

Name

CURLOPT_DEBUGDATA - pointer passed to the debug callback

Synopsis

#include <curl/curl.h>
 
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DEBUGDATA, void *pointer);

Description

Pass a pointer to whatever you want passed in to your CURLOPT_DEBUGFUNCTION in the last void * argument. This pointer is not used by libcurl, it is only passed to the callback.

Default

NULL

Protocols

This functionality affects all supported protocols

Example

struct data {
  void *custom;
};
 
static int my_trace(CURL *handle, curl_infotype type,
                    char *data, size_t size,
                    void *clientp)
{
  struct data *mine = clientp;
  printf("our ptr: %p\n", mine->custom);
 
  /* output debug info */
}
 
int main(void)
{
  CURL *curl;
  CURLcode res;
  struct data my_tracedata;
 
  curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, my_trace);
 
    curl_easy_setopt(curl, CURLOPT_DEBUGDATA, &my_tracedata);
 
    /* the DEBUGFUNCTION has no effect until we enable VERBOSE */
    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
 
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    res = curl_easy_perform(curl);
 
    /* always cleanup */
    curl_easy_cleanup(curl);
  }
  return 0;
}

Availability

Added in curl 7.9.6

Return value

Returns CURLE_OK