CURLOPT_SOCKOPTDATA

Section: curl_easy_setopt options (3)
Updated: November 04, 2020
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NAME

CURLOPT_SOCKOPTDATA - custom pointer to pass to sockopt callback

SYNOPSIS

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

DESCRIPTION

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

DEFAULT

The default value of this parameter is NULL.

PROTOCOLS

All

EXAMPLE

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);
}

AVAILABILITY

Added in 7.16.0

RETURN VALUE

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