NAME¶
malloc_usable_size - obtain size of block of memory allocated from heap
SYNOPSIS¶
#include <malloc.h>
size_t malloc_usable_size (void *ptr);
DESCRIPTION¶
The
malloc_usable_size() function returns the number of usable bytes in
the block pointed to by
ptr, a pointer to a block of memory allocated
by
malloc(3) or a related function.
RETURN VALUE¶
malloc_usable_size() returns the number of usable bytes in the block of
allocated memory pointed to by
ptr. If
ptr is NULL, 0 is
returned.
ATTRIBUTES¶
Multithreading (see pthreads(7))¶
The
malloc_usable_size() function is thread-safe.
This function is a GNU extension.
NOTES¶
The value returned by
malloc_usable_size() may be greater than the
requested size of the allocation because of alignment and minimum size
constraints. Although the excess bytes can be overwritten by the application
without ill effects, this is not good programming practice: the number of
excess bytes in an allocation depends on the underlying implementation.
The main use of this function is for debugging and introspection.
SEE ALSO¶
malloc(3)
COLOPHON¶
This page is part of release 3.74 of the Linux
man-pages project. A
description of the project, information about reporting bugs, and the latest
version of this page, can be found at
http://www.kernel.org/doc/man-pages/.
