1MALLOC_USABLE_SIZE(3)      Linux Programmer's Manual     MALLOC_USABLE_SIZE(3)
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NAME

6       malloc_usable_size - obtain size of block of memory allocated from heap
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SYNOPSIS

9       #include <malloc.h>
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11       size_t malloc_usable_size (void *ptr);
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DESCRIPTION

14       The malloc_usable_size() function returns the number of usable bytes in
15       the block pointed to by ptr, a pointer to a block of  memory  allocated
16       by malloc(3) or a related function.
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RETURN VALUE

19       malloc_usable_size() returns the number of usable bytes in the block of
20       allocated memory pointed to by ptr.  If ptr is NULL, 0 is returned.
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CONFORMING TO

23       This function is a GNU extension.
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NOTES

26       The value returned by malloc_usable_size()  may  be  greater  than  the
27       requested  size of the allocation because of alignment and minimum size
28       constraints.  Although the excess  bytes  can  be  overwritten  by  the
29       application without ill effects, this is not good programming practice:
30       the number of excess bytes in an allocation depends on  the  underlying
31       implementation.
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33       The main use of this function is for debugging and introspection.
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SEE ALSO

36       malloc(3)
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COLOPHON

39       This  page  is  part of release 3.53 of the Linux man-pages project.  A
40       description of the project, and information about reporting  bugs,  can
41       be found at http://www.kernel.org/doc/man-pages/.
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45GNU                               2012-03-29             MALLOC_USABLE_SIZE(3)
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