curl/docs/libcurl/opts/CURLINFO_ACTIVESOCKET.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

1.9 KiB

c SPDX-License-Identifier Title Section Source See-also
Copyright (C) Daniel Stenberg, <daniel.se>, et al. curl CURLINFO_ACTIVESOCKET 3 libcurl
CURLINFO_LASTSOCKET (3)
CURLOPT_CONNECT_ONLY (3)
curl_easy_getinfo (3)
curl_easy_setopt (3)

NAME

CURLINFO_ACTIVESOCKET - get the active socket

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_ACTIVESOCKET,
                           curl_socket_t *socket);

DESCRIPTION

Pass a pointer to a curl_socket_t to receive the most recently active socket used for the transfer connection by this curl session. If the socket is no longer valid, CURL_SOCKET_BAD is returned. When you are finished working with the socket, you must call curl_easy_cleanup(3) as usual on the easy handle and let libcurl close the socket and cleanup other resources associated with the handle. This option returns the active socket only after the transfer is complete, and is typically used in combination with CURLOPT_CONNECT_ONLY(3), which skips the transfer phase.

CURLINFO_ACTIVESOCKET(3) was added as a replacement for CURLINFO_LASTSOCKET(3) since that one is not working on all platforms.

PROTOCOLS

All

EXAMPLE

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_socket_t sockfd;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

    /* Do not do the transfer - only connect to host */
    curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 1L);
    res = curl_easy_perform(curl);

    /* Extract the socket from the curl handle */
    res = curl_easy_getinfo(curl, CURLINFO_ACTIVESOCKET, &sockfd);

    if(res != CURLE_OK) {
      printf("Error: %s\n", curl_easy_strerror(res));
      return 1;
    }
  }
}

AVAILABILITY

Added in 7.45.0

RETURN VALUE

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