curl_global_init_mem.md (2603B)
1 --- 2 c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3 SPDX-License-Identifier: curl 4 Title: curl_global_init_mem 5 Section: 3 6 Source: libcurl 7 See-also: 8 - curl_global_cleanup (3) 9 - curl_global_init (3) 10 Protocol: 11 - All 12 Added-in: 7.12.0 13 --- 14 15 # NAME 16 17 curl_global_init_mem - global libcurl initialization with memory callbacks 18 19 # SYNOPSIS 20 21 ~~~c 22 #include <curl/curl.h> 23 24 CURLcode curl_global_init_mem(long flags, 25 curl_malloc_callback m, 26 curl_free_callback f, 27 curl_realloc_callback r, 28 curl_strdup_callback s, 29 curl_calloc_callback c); 30 ~~~ 31 32 # DESCRIPTION 33 34 This function works exactly as curl_global_init(3) with one addition: it 35 allows the application to set callbacks to replace the otherwise used internal 36 memory functions. 37 38 If you are using libcurl from multiple threads or libcurl was built with the 39 threaded resolver option then the callback functions must be thread safe. The 40 threaded resolver is a common build option to enable (and in some cases the 41 default) so we strongly urge you to make your callback functions thread safe. 42 43 All callback arguments must be set to valid function pointers. The 44 prototypes for the given callbacks must match these: 45 46 ## `void *malloc_callback(size_t size);` 47 48 To replace malloc() 49 50 ## `void free_callback(void *ptr);` 51 52 To replace free() 53 54 ## `void *realloc_callback(void *ptr, size_t size);` 55 56 To replace realloc() 57 58 ## `char *strdup_callback(const char *str);` 59 60 To replace strdup() 61 62 ## `void *calloc_callback(size_t nmemb, size_t size);` 63 64 To replace calloc() 65 66 This function is otherwise the same as curl_global_init(3), please refer 67 to that man page for documentation. 68 69 # CAUTION 70 71 Manipulating these gives considerable powers to the application to severely 72 screw things up for libcurl. Take care. 73 74 # %PROTOCOLS% 75 76 # EXAMPLE 77 78 ~~~c 79 extern void *malloc_cb(size_t); 80 extern void free_cb(void *); 81 extern void *realloc_cb(void *, size_t); 82 extern char *strdup_cb(const char *); 83 extern void *calloc_cb(size_t, size_t); 84 85 int main(void) 86 { 87 curl_global_init_mem(CURL_GLOBAL_DEFAULT, malloc_cb, 88 free_cb, realloc_cb, 89 strdup_cb, calloc_cb); 90 } 91 ~~~ 92 93 # %AVAILABILITY% 94 95 # RETURN VALUE 96 97 This function returns a CURLcode indicating success or error. 98 99 CURLE_OK (0) means everything was OK, non-zero means an error occurred, see 100 libcurl-errors(3). If CURLOPT_ERRORBUFFER(3) was set with curl_easy_setopt(3) 101 there can be an error message stored in the error buffer when non-zero is 102 returned.