curl/docs/libcurl/opts/CURLOPT_OPENSOCKETDATA.md
Daniel Stenberg e3fe020089
docs/libcurl: generate PROTOCOLS from meta-data
Remove the PROTOCOLS section from the source files completely and
instead generate them based on the header data in the curldown files.

It also generates TLS backend information for options marked for TLS as
protocol.

Closes #13175
2024-03-23 18:13:03 +01:00

2.1 KiB

c SPDX-License-Identifier Title Section Source See-also Protocol
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. curl CURLOPT_OPENSOCKETDATA 3 libcurl
CURLOPT_CLOSESOCKETFUNCTION (3)
CURLOPT_OPENSOCKETFUNCTION (3)
CURLOPT_SOCKOPTFUNCTION (3)
All

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.

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.