.\" generated by cd2nroff 0.1 from CURLOPT_CLOSESOCKETFUNCTION.md
.TH CURLOPT_CLOSESOCKETFUNCTION 3 "2024-11-18" libcurl
.SH NAME
CURLOPT_CLOSESOCKETFUNCTION \- callback to socket close replacement
.SH SYNOPSIS
.nf
#include <curl/curl.h>

int closesocket_callback(void *clientp, curl_socket_t item);

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CLOSESOCKETFUNCTION,
                          closesocket_callback);
.fi
.SH DESCRIPTION
Pass a pointer to your callback function, which should match the prototype
shown above.

This callback function gets called by libcurl instead of the \fIclose(3)\fP or
\fIclosesocket(3)\fP call when sockets are closed (not for any other file
descriptors). This is pretty much the reverse to the
\fICURLOPT_OPENSOCKETFUNCTION(3)\fP option. Return 0 to signal success and 1
if there was an error.

The \fIclientp\fP pointer is set with
\fICURLOPT_CLOSESOCKETDATA(3)\fP. \fIitem\fP is the socket libcurl wants to be
closed.
.SH DEFAULT
Use the standard socket close function.
.SH PROTOCOLS
This functionality affects all supported protocols
.SH EXAMPLE
.nf
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);
}
.fi
.SH AVAILABILITY
Added in curl 7.21.7
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH SEE ALSO
.BR CURLOPT_CLOSESOCKETDATA (3),
.BR CURLOPT_OPENSOCKETFUNCTION (3)