trusty (3) malloc_usable_size.3.gz

Provided by: manpages-dev_3.54-1ubuntu1_all bug

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.


CONFORMING TO
       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 3.54 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/.