Manpages - CURLOPT_OPENSOCKETDATA.3

CURLOPT_OPENSOCKETDATA - pointer passed to open socket callback

#include <curl/curl.h>

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

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

The default value of this parameter is NULL.

All

  /* make libcurl use the already established socket 'sockfd' */

  static curl_socket_t opensocket(void *clientp,
                                  curlsocktype purpose,
                                  struct curl_sockaddr *address)
  {
    curl_socket_t sockfd;
    sockfd = *(curl_socket_t *)clientp;
    /* the actual externally set socket is passed in via the OPENSOCKETDATA
       option */
    return sockfd;
  }

  static int sockopt_callback(void *clientp, curl_socket_t curlfd,
                              curlsocktype purpose)
  {
    /* This return code was added in libcurl 7.21.5 */
    return CURL_SOCKOPT_ALREADY_CONNECTED;
  }

  curl = curl_easy_init();
  if(curl) {
    /* libcurl will internally think that you connect to the host
     * and port that you specify in the URL option. */
    curl_easy_setopt(curl, CURLOPT_URL, "http://99.99.99.99:9999");
    /* call this function to get a socket */
    curl_easy_setopt(curl, CURLOPT_OPENSOCKETFUNCTION, opensocket);
    curl_easy_setopt(curl, CURLOPT_OPENSOCKETDATA, &sockfd);

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

    res = curl_easy_perform(curl);

    curl_easy_cleanup(curl);
  }

Added in 7.17.1

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

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