NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

MALLOC_USABLE_SIZE(3)     Linux Programmer's Manual    MALLOC_USABLE_SIZE(3)

NAME         top

       malloc_usable_size  -  obtain  size of block of memory allocated from
       heap

SYNOPSIS         top

       #include <malloc.h>

       size_t malloc_usable_size (void *ptr);

DESCRIPTION         top

       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         top

       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.

CONFORMING TO         top

       This function is a GNU extension.

NOTES         top

       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         top

       malloc(3)

COLOPHON         top

       This page is part of release 3.65 of the Linux man-pages project.  A
       description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

GNU                              2012-03-29            MALLOC_USABLE_SIZE(3)