curl/docs/libcurl/curl_global_init_mem.md
Daniel Stenberg 96af350661
libcurl-docs: cleanups
CURLMOPT_SOCKETDATA.md: fix typo
 CURLMOPT_TIMERDATA.md: fix typo
 CURLOPT_COOKIELIST.m: quote strings
 CURLOPT_PREREQFUNCTION.md: quote variable names
 CURLOPT_TCP_NODELAY.md: rephrased to please spell checker
 CURLOPT_WILDCARDMATCH.md: rephrased
 libcurl-tutorial.md: use correct option name
 curl_global_init_mem.md: quote headers
 curl_easy_getinfo.md: use correct symbol names in headers
 curl_global_trace.md: quote some headers
 curl_ws_meta.md: quote struct field names
 libcurl-env.md: quote headers
2024-02-19 11:41:12 +01:00

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---
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).