malloc_trim


SYNOPSIS
       #include <malloc.h>

       void malloc_trim(size_t pad);

DESCRIPTION
       The  malloc_trim()  function attempts to release free memory at the top
       of the heap (by calling sbrk(2) with a suitable argument).

       The pad argument specifies the amount of free space to leave  untrimmed
       at the top of the heap.  If this argument is 0, only the minimum amount
       of memory is maintained at the top of  the  heap  (i.e.,  one  page  or
       less).   A nonzero argument can be used to maintain some trailing space
       at the top of the heap in order to allow future allocations to be  made
       without having to extend the heap with sbrk(2).

RETURN VALUE
       The  malloc_trim()  function  returns 1 if memory was actually released
       back to the system, or 0 if it was not possible to release any memory.

ERRORS
       No errors are defined.

CONFORMING TO
       This function is a GNU extension.

NOTES
       This function is automatically called by  free(3)  in  certain  circum-
       stances;  see  the discussion of M_TOP_PAD and M_TRIM_THRESHOLD in mal-
       lopt(3).

       This function cannot release free memory located at places  other  than
       the top of the heap.

       This function releases only memory in the main arena.

SEE ALSO
       sbrk(2), malloc(3), mallopt(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/.



Linux                             2012-03-29                    MALLOC_TRIM(3)
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