curl/docs/libcurl/curl_ws_recv.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

1.7 KiB

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

NAME

curl_ws_recv - receive WebSocket data

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_ws_recv(CURL *curl, void *buffer, size_t buflen,
                      size_t *recv, const struct curl_ws_frame **meta);

DESCRIPTION

This function call is EXPERIMENTAL.

Retrieves as much as possible of a received WebSocket data fragment into the buffer, but not more than buflen bytes. recv is set to the number of bytes actually stored.

If there is more fragment data to deliver than what fits in the provided buffer, libcurl returns a full buffer and the application needs to call this function again to continue draining the buffer.

The meta pointer gets set to point to a const struct curl_ws_frame that contains information about the received data. See the curl_ws_meta(3) for details on that struct.

EXAMPLE

int main(void)
{
  size_t rlen;
  const struct curl_ws_frame *meta;
  char buffer[256];
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res = curl_ws_recv(curl, buffer, sizeof(buffer), &rlen, &meta);
    if(res)
      printf("error: %s\n", curl_easy_strerror(res));
  }
}

AVAILABILITY

Added in 7.86.0.

RETURN VALUE

Returns CURLE_OK if everything is okay, and a non-zero number for errors. Returns CURLE_GOT_NOTHING if the associated connection is closed.

Instead of blocking, the function returns CURLE_AGAIN. The correct behavior is then to wait for the socket to signal readability before calling this function again.