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| author | Alejandro Colomar <alx.manpages@gmail.com> | 2022-09-05 23:03:38 +0200 |
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| committer | Alejandro Colomar <alx.manpages@gmail.com> | 2022-09-05 23:03:47 +0200 |
| commit | 70ac1c4785fc1e158ab2349a962dba2526bf4fbc (patch) | |
| tree | bff270e2496dd284bccfc1271b43946f5d225224 /man3/malloc_hook.3 | |
| parent | 5423a6f86b2b920a5f3e8cf8d759b513050f2d33 (diff) | |
| download | man-pages-70ac1c4785fc1e158ab2349a962dba2526bf4fbc.tar.gz | |
src.mk, All pages: Move man* to man/
The root of the repository is becoming a bit overpopulated and
unorganized, due to the recent addition of more mandirs, and more
informative and configuration files too. Let's create a specific
mandir <man/> that contains the mandirs <man[1-8]*>.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Diffstat (limited to 'man3/malloc_hook.3')
| -rw-r--r-- | man3/malloc_hook.3 | 154 |
1 files changed, 0 insertions, 154 deletions
diff --git a/man3/malloc_hook.3 b/man3/malloc_hook.3 deleted file mode 100644 index 08668aa720..0000000000 --- a/man3/malloc_hook.3 +++ /dev/null @@ -1,154 +0,0 @@ -.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) -.\" -.\" SPDX-License-Identifier: GPL-1.0-or-later -.\" -.\" Heavily based on glibc documentation -.\" Polished, added docs, removed glibc doc bug, 2002-07-20, aeb -.\" -.TH MALLOC_HOOK 3 2021-03-22 "Linux man-pages (unreleased)" -.SH NAME -__malloc_hook, __malloc_initialize_hook, -__memalign_hook, __free_hook, __realloc_hook, -__after_morecore_hook \- malloc debugging variables (DEPRECATED) -.SH LIBRARY -Standard C library -.RI ( libc ", " \-lc ) -.SH SYNOPSIS -.nf -.B "#include <malloc.h>" -.PP -.BI "void *(*volatile __malloc_hook)(size_t " size ", const void *" caller ); -.PP -.BI "void *(*volatile __realloc_hook)(void *" ptr ", size_t " size , -.BI " const void *" caller ); -.PP -.BI "void *(*volatile __memalign_hook)(size_t " alignment ", size_t " size , -.BI " const void *" caller ); -.PP -.BI "void (*volatile __free_hook)(void *" ptr ", const void *" caller ); -.PP -.B "void (*__malloc_initialize_hook)(void);" -.PP -.B "void (*volatile __after_morecore_hook)(void);" -.fi -.SH DESCRIPTION -The GNU C library lets you modify the behavior of -.BR malloc (3), -.BR realloc (3), -and -.BR free (3) -by specifying appropriate hook functions. -You can use these hooks -to help you debug programs that use dynamic memory allocation, -for example. -.PP -The variable -.B __malloc_initialize_hook -points at a function that is called once when the malloc implementation -is initialized. -This is a weak variable, so it can be overridden in -the application with a definition like the following: -.PP -.in +4n -.EX -void (*__malloc_initialize_hook)(void) = my_init_hook; -.EE -.in -.PP -Now the function -.IR my_init_hook () -can do the initialization of all hooks. -.PP -The four functions pointed to by -.BR __malloc_hook , -.BR __realloc_hook , -.BR __memalign_hook , -.B __free_hook -have a prototype like the functions -.BR malloc (3), -.BR realloc (3), -.BR memalign (3), -.BR free (3), -respectively, except that they have a final argument -.I caller -that gives the address of the caller of -.BR malloc (3), -etc. -.PP -The variable -.B __after_morecore_hook -points at a function that is called each time after -.BR sbrk (2) -was asked for more memory. -.SH STANDARDS -These functions are GNU extensions. -.SH NOTES -The use of these hook functions is not safe in multithreaded programs, -and they are now deprecated. -From glibc 2.24 onwards, the -.B __malloc_initialize_hook -variable has been removed from the API, -and from glibc 2.34 onwards, all -the hook variables have been removed from the API. -.\" https://bugzilla.redhat.com/show_bug.cgi?id=450187 -.\" http://sourceware.org/bugzilla/show_bug.cgi?id=9957 -Programmers should instead preempt calls to the relevant functions -by defining and exporting -.BR malloc (), -.BR free (), -.BR realloc (), -and -.BR calloc (). -.SH EXAMPLES -Here is a short example of how to use these variables. -.PP -.EX -#include <stdio.h> -#include <malloc.h> - -/* Prototypes for our hooks */ -static void my_init_hook(void); -static void *my_malloc_hook(size_t, const void *); - -/* Variables to save original hooks */ -static void *(*old_malloc_hook)(size_t, const void *); - -/* Override initializing hook from the C library */ -void (*__malloc_initialize_hook)(void) = my_init_hook; - -static void -my_init_hook(void) -{ - old_malloc_hook = __malloc_hook; - __malloc_hook = my_malloc_hook; -} - -static void * -my_malloc_hook(size_t size, const void *caller) -{ - void *result; - - /* Restore all old hooks */ - __malloc_hook = old_malloc_hook; - - /* Call recursively */ - result = malloc(size); - - /* Save underlying hooks */ - old_malloc_hook = __malloc_hook; - - /* printf() might call malloc(), so protect it too */ - printf("malloc(%zu) called from %p returns %p\en", - size, caller, result); - - /* Restore our own hooks */ - __malloc_hook = my_malloc_hook; - - return result; -} -.EE -.SH SEE ALSO -.BR mallinfo (3), -.BR malloc (3), -.BR mcheck (3), -.BR mtrace (3) |