CURLOPT_OPENSOCKETDATA

Section: C Library Functions (3)
Updated: 202-0-19
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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

NULL  

PROTOCOLS

This functionality affects all supported protocols  

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)
{
  return CURL_SOCKOPT_ALREADY_CONNECTED;
}

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    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);

    result = curl_easy_perform(curl);

    curl_easy_cleanup(curl);
  }
}

 

AVAILABILITY

Added in curl 7.17.1  

RETURN VALUE

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).  

SEE ALSO

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

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Index

NAME

SYNOPSIS

DESCRIPTION

DEFAULT

PROTOCOLS

EXAMPLE

AVAILABILITY

RETURN VALUE

SEE ALSO