curl/docs/libcurl/opts/CURLOPT_CLOSESOCKETFUNCTION.md
Daniel Stenberg eefcc1bda4
docs: introduce "curldown" for libcurl man page format
curldown is this new file format for libcurl man pages. It is markdown
inspired with differences:

- Each file has a set of leading headers with meta-data
- Supports a small subset of markdown
- Uses .md file extensions for editors/IDE/GitHub to treat them nicely
- Generates man pages very similar to the previous ones
- Generates man pages that still convert nicely to HTML on the website
- Detects and highlights mentions of curl symbols automatically (when
  their man page section is specified)

tools:

- cd2nroff: converts from curldown to nroff man page
- nroff2cd: convert an (old) nroff man page to curldown
- cdall: convert many nroff pages to curldown versions
- cd2cd: verifies and updates a curldown to latest curldown

This setup generates .3 versions of all the curldown versions at build time.

CI:

Since the documentation is now technically markdown in the eyes of many
things, the CI runs many more tests and checks on this documentation,
including proselint, link checkers and tests that make sure we capitalize the
first letter after a period...

Closes #12730
2024-01-23 00:29:02 +01:00

1.8 KiB

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

NAME

CURLOPT_CLOSESOCKETFUNCTION - callback to socket close replacement

SYNOPSIS

#include <curl/curl.h>

int closesocket_callback(void *clientp, curl_socket_t item);

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CLOSESOCKETFUNCTION,
                          closesocket_callback);

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 close(3) or closesocket(3) call when sockets are closed (not for any other file descriptors). This is pretty much the reverse to the CURLOPT_OPENSOCKETFUNCTION(3) option. Return 0 to signal success and 1 if there was an error.

The clientp pointer is set with CURLOPT_CLOSESOCKETDATA(3). item is the socket libcurl wants to be closed.

DEFAULT

By default libcurl uses the standard socket close function.

PROTOCOLS

All

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 7.21.7

RETURN VALUE

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