malloc_trim(3) - Linux manual page (original) (raw)

malloctrim(3) Library Functions Manual malloctrim(3)

NAME top

   malloc_trim - release free memory from the heap

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <malloc.h>**

   **int malloc_trim(size_t** _pad_**);**

DESCRIPTION top

   The **malloc_trim**() function attempts to release free memory from
   the heap (by calling [sbrk(2)](../man2/sbrk.2.html) or [madvise(2)](../man2/madvise.2.html) 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)](../man2/sbrk.2.html).

RETURN VALUE top

   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 top

   No errors are defined.

ATTRIBUTES top

   For an explanation of the terms used in this section, see
   [attributes(7)](../man7/attributes.7.html).
   ┌──────────────────────────────────────┬───────────────┬─────────┐
   │ **Interface** │ **Attribute** │ **Value** │
   ├──────────────────────────────────────┼───────────────┼─────────┤
   │ **malloc_trim**()                        │ Thread safety │ MT-Safe │
   └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS top

   GNU.

VERSIONS top

   glibc 2.0.

NOTES top

   Only the main heap (using [sbrk(2)](../man2/sbrk.2.html)) 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 top

   [sbrk(2)](../man2/sbrk.2.html), [malloc(3)](../man3/malloc.3.html), [mallopt(3)](../man3/mallopt.3.html)

COLOPHON top

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Linux man-pages 6.10 2024-07-23 malloctrim(3)

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