Manpages - CURLOPT_SOCKOPTDATA.3

CURLOPT_SOCKOPTDATA - pointer to pass to sockopt callback

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SOCKOPTDATA, void *pointer);

Pass a pointer that will be untouched by libcurl and passed as the first argument in the sockopt callback set with CURLOPT_SOCKOPTFUNCTION(3).

The default value of this parameter is NULL.

All

  static int sockopt_callback(void *clientp, curl_socket_t curlfd,
                              curlsocktype purpose)
  {
    int val = *(int *)clientp;
    setsockopt(curldfd, SOL_SOCKET, SO_RCVBUF, (const char *)&val, sizeof(val));
    return CURL_SOCKOPT_OK;
  }

  curl = curl_easy_init();
  if(curl) {
    int recvbuffersize = 256 * 1024;

    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");

    /* call this function to set options for the socket */
    curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
    curl_easy_setopt(curl, CURLOPT_SOCKOPTDATA, &recvbuffersize);

    res = curl_easy_perform(curl);

    curl_easy_cleanup(curl);
  }

Added in 7.16.0

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

*CURLOPT_SOCKOPTFUNCTION*(3), *CURLOPT_OPENSOCKETFUNCTION*(3),