curl/docs/libcurl/opts/CURLMOPT_SOCKETDATA.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

83 lines
1.4 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
SPDX-License-Identifier: curl
Title: CURLMOPT_SOCKETDATA
Section: 3
Source: libcurl
See-also:
- CURLMOPT_SOCKETFUNCTION (3)
- CURLMOPT_TIMERFUNCTION (3)
- curl_multi_socket_action (3)
---
# NAME
CURLMOPT_SOCKETDATA - custom pointer passed to the socket callback
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_SOCKETDATA, void *pointer);
~~~
# DESCRIPTION
A data *pointer* to pass to the socket callback set with the
CURLMOPT_SOCKETFUNCTION(3) option.
This pointer is not touched by libcurl but is only passed in as the socket
callbacks's **clientp** argument.
# DEFAULT
NULL
# PROTOCOLS
All
# EXAMPLE
~~~c
struct priv {
void *ours;
};
static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
{
struct priv *p = sockp;
printf("my ptr: %p\n", p->ours);
if(what == CURL_POLL_REMOVE) {
/* remove the socket from our collection */
}
if(what & CURL_POLL_IN) {
/* wait for read on this socket */
}
if(what & CURL_POLL_OUT) {
/* wait for write on this socket */
}
return 0;
}
int main(void)
{
struct priv setup;
CURLM *multi = curl_multi_init();
/* ... use socket callback and custom pointer */
curl_multi_setopt(multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
curl_multi_setopt(multi, CURLMOPT_SOCKETDATA, &setup);
}
~~~
# AVAILABILITY
Added in 7.15.4
# RETURN VALUE
Returns CURLM_OK.