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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
MALLOC_TRIM(3) Linux Programmer's Manual MALLOC_TRIM(3)
malloc_trim - release free memory from the heap
#include <malloc.h>
int malloc_trim(size_t pad);
The malloc_trim() function attempts to release free memory from the
heap (by calling sbrk(2) or madvise(2) with suitable arguments).
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).
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.
No errors are defined.
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────────┼───────────────┼─────────┤
│malloc_trim() │ Thread safety │ MT-Safe │
└──────────────┴───────────────┴─────────┘
This function is a GNU extension.
This function is automatically called by free(3) in certain
circumstances; see the discussion of M_TOP_PAD and M_TRIM_THRESHOLD
in mallopt(3).
Only the main heap (using sbrk(2)) honors the pad argument; thread
heaps do not.
Since glibc 2.8 this function frees memory in all arenas and in all
chunks with whole free pages.
Before glibc 2.8 this function only freed memory at the top of the
heap in the main arena.
sbrk(2), malloc(3), mallopt(3)
This page is part of release 5.08 of the Linux man-pages project. A
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latest version of this page, can be found at
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Linux 2020-08-13 MALLOC_TRIM(3)
Pages that refer to this page: calloc(3) , free(3) , mallinfo(3) , malloc(3) , mallopt(3) , realloc(3) , reallocarray(3)
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