CURLOPT_DEBUGDATA(3) Introduction to Library Functions CURLOPT_DEBUGDATA(3)

CURLOPT_DEBUGDATA - pointer passed to the debug callback

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

Pass a pointer to whatever you want passed in to your CURLOPT_DEBUGFUNCTION(3) in the last void * argument. This pointer is not used by libcurl, it is only passed to the callback.

NULL

This functionality affects all supported protocols

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;
}

Added in curl 7.9.6

Returns CURLE_OK

CURLOPT_DEBUGFUNCTION(3), CURLOPT_STDERR(3)

2024-10-05 libcurl