malloc_trim(3) — Linux manual page

malloc_trim(3)          Library Functions Manual          malloc_trim(3)

NAME

       malloc_trim - release free memory from the heap

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <malloc.h>

       int malloc_trim(size_t pad);

DESCRIPTION

       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).

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.

ATTRIBUTES

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌─────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                           │ Attribute     │ Value   │
       ├─────────────────────────────────────┼───────────────┼─────────┤
       │ malloc_trim()                       │ Thread safety │ MT-Safe │
       └─────────────────────────────────────┴───────────────┴─────────┘

STANDARDS

       GNU.

VERSIONS

       glibc 2.0.

NOTES

       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.

SEE ALSO

       sbrk(2), malloc(3), mallopt(3)

COLOPHON

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Linux man-pages 6.9.1          2024-05-02                 malloc_trim(3)

Pages that refer to this page: mallinfo(3), malloc(3), mallopt(3), sd_event_add_memory_pressure(3)

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