curl/docs/libcurl/curl_global_init_mem.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

96 lines
2.3 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel.se>, et al.
SPDX-License-Identifier: curl
Title: curl_global_init_mem
Section: 3
Source: libcurl
See-also:
- curl_global_cleanup (3)
- curl_global_init (3)
---
# NAME
curl_global_init_mem - Global libcurl initialization with memory callbacks
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLcode curl_global_init_mem(long flags,
curl_malloc_callback m,
curl_free_callback f,
curl_realloc_callback r,
curl_strdup_callback s,
curl_calloc_callback c);
~~~
# DESCRIPTION
This function works exactly as curl_global_init(3) with one addition: it
allows the application to set callbacks to replace the otherwise used internal
memory functions.
If you are using libcurl from multiple threads or libcurl was built with the
threaded resolver option then the callback functions must be thread safe. The
threaded resolver is a common build option to enable (and in some cases the
default) so we strongly urge you to make your callback functions thread safe.
All callback arguments must be set to valid function pointers. The
prototypes for the given callbacks must match these:
## void *malloc_callback(size_t size);
To replace malloc()
## void free_callback(void *ptr);
To replace free()
## void *realloc_callback(void *ptr, size_t size);
To replace realloc()
## char *strdup_callback(const char *str);
To replace strdup()
## void *calloc_callback(size_t nmemb, size_t size);
To replace calloc()
This function is otherwise the same as curl_global_init(3), please refer
to that man page for documentation.
# CAUTION
Manipulating these gives considerable powers to the application to severely
screw things up for libcurl. Take care!
# EXAMPLE
~~~c
extern void *malloc_cb(size_t);
extern void free_cb(void *);
extern void *realloc_cb(void *, size_t);
extern char *strdup_cb(const char *);
extern void *calloc_cb(size_t, size_t);
int main(void)
{
curl_global_init_mem(CURL_GLOBAL_DEFAULT, malloc_cb,
free_cb, realloc_cb,
strdup_cb, calloc_cb);
}
~~~
# AVAILABILITY
Added in 7.12.0
# RETURN VALUE
CURLE_OK (0) means everything was OK, non-zero means an error occurred as
*<curl/curl.h>* defines - see libcurl-errors(3).