NAME

       CURLOPT_OPENSOCKETDATA - pointer passed to open socket callback

SYNOPSIS

       #include <curl/curl.h>

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

DESCRIPTION

       Pass  a  pointer that is untouched by libcurl and passed as the first argument in the open
       socket callback set with CURLOPT_OPENSOCKETFUNCTION(3).

DEFAULT

       The default value of this parameter is NULL.

PROTOCOLS

       All

EXAMPLE

       /* 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;
       }

       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           CURLcode res;
           extern int sockfd; /* the already connected one */

           /* libcurl thinks 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);
         }
       }

AVAILABILITY

       Added in 7.17.1

RETURN VALUE

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

SEE ALSO

       CURLOPT_CLOSESOCKETFUNCTION(3), CURLOPT_OPENSOCKETFUNCTION(3), CURLOPT_SOCKOPTFUNCTION(3)