curl/docs/libcurl/opts/CURLOPT_CHUNK_DATA.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

103 lines
1.9 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_CHUNK_DATA
Section: 3
Source: libcurl
See-also:
- CURLOPT_CHUNK_BGN_FUNCTION (3)
- CURLOPT_WILDCARDMATCH (3)
---
# NAME
CURLOPT_CHUNK_DATA - pointer passed to the FTP chunk callbacks
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CHUNK_DATA, void *pointer);
~~~
# DESCRIPTION
Pass a *pointer* that is untouched by libcurl and passed as the ptr
argument to the CURLOPT_CHUNK_BGN_FUNCTION(3) and
CURLOPT_CHUNK_END_FUNCTION(3).
# DEFAULT
NULL
# PROTOCOLS
FTP
# EXAMPLE
~~~c
#include <stdio.h>
struct callback_data {
FILE *output;
};
static long file_is_coming(struct curl_fileinfo *finfo,
void *ptr,
int remains)
{
struct callback_data *data = ptr;
printf("%3d %40s %10luB ", remains, finfo->filename,
(unsigned long)finfo->size);
switch(finfo->filetype) {
case CURLFILETYPE_DIRECTORY:
printf(" DIR\n");
break;
case CURLFILETYPE_FILE:
printf("FILE ");
break;
default:
printf("OTHER\n");
break;
}
if(finfo->filetype == CURLFILETYPE_FILE) {
/* do not transfer files >= 50B */
if(finfo->size > 50) {
printf("SKIPPED\n");
return CURL_CHUNK_BGN_FUNC_SKIP;
}
data->output = fopen(finfo->filename, "wb");
if(!data->output) {
return CURL_CHUNK_BGN_FUNC_FAIL;
}
}
return CURL_CHUNK_BGN_FUNC_OK;
}
int main()
{
/* data for callback */
struct callback_data callback_info;
CURL *curl = curl_easy_init();
/* callback is called before download of concrete file started */
curl_easy_setopt(curl, CURLOPT_CHUNK_BGN_FUNCTION, file_is_coming);
curl_easy_setopt(curl, CURLOPT_CHUNK_DATA, &callback_info);
}
~~~
# AVAILABILITY
Added in 7.21.0
# RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.