curl / libcurl / API / curl_easy_setopt / CURLOPT_CLOSESOCKETDATA

CURLOPT_CLOSESOCKETDATA explained

Name

CURLOPT_CLOSESOCKETDATA - pointer passed to the socket close callback

Synopsis

#include <curl/curl.h>
 
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CLOSESOCKETDATA,
                          void *pointer);

Description

Pass a pointer that remains untouched by libcurl and passed as the first argument in the closesocket callback set with CURLOPT_CLOSESOCKETFUNCTION.

Note that when using multi/share handles, your callback may get invoked even after the easy handle has been cleaned up. The callback and data is inherited by a new connection and that connection may live longer than the transfer itself in the multi/share handle's connection cache.

Default

NULL

Protocols

This functionality affects all supported protocols

Example

struct priv {
  void *custom;
};
 
static int closesocket(void *clientp, curl_socket_t item)
{
  struct priv *my = clientp;
  printf("our ptr: %p\n", my->custom);
 
  printf("libcurl wants to close %d now\n", (int)item);
  return 0;
}
 
int main(void)
{
  struct priv myown;
  CURL *curl = curl_easy_init();
 
  /* call this function to close sockets */
  curl_easy_setopt(curl, CURLOPT_CLOSESOCKETFUNCTION, closesocket);
  curl_easy_setopt(curl, CURLOPT_CLOSESOCKETDATA, &myown);
 
  curl_easy_perform(curl);
  curl_easy_cleanup(curl);
}

Availability

Added in curl 7.21.7

Return value

curl_easy_setopt returns a CURLcode indicating success or error.

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