mirror of https://github.com/mkerrisk/man-pages
82 lines
2.7 KiB
Groff
82 lines
2.7 KiB
Groff
'\" t
|
|
.\" Copyright (c) 2012 by Michael Kerrisk <mtk.manpages@gmail.com>
|
|
.\"
|
|
.\" %%%LICENSE_START(VERBATIM)
|
|
.\" Permission is granted to make and distribute verbatim copies of this
|
|
.\" manual provided the copyright notice and this permission notice are
|
|
.\" preserved on all copies.
|
|
.\"
|
|
.\" Permission is granted to copy and distribute modified versions of this
|
|
.\" manual under the conditions for verbatim copying, provided that the
|
|
.\" entire resulting derived work is distributed under the terms of a
|
|
.\" permission notice identical to this one.
|
|
.\"
|
|
.\" Since the Linux kernel and libraries are constantly changing, this
|
|
.\" manual page may be incorrect or out-of-date. The author(s) assume no
|
|
.\" responsibility for errors or omissions, or for damages resulting from
|
|
.\" the use of the information contained herein. The author(s) may not
|
|
.\" have taken the same level of care in the production of this manual,
|
|
.\" which is licensed free of charge, as they might when working
|
|
.\" professionally.
|
|
.\"
|
|
.\" Formatted or processed versions of this manual, if unaccompanied by
|
|
.\" the source, must acknowledge the copyright and authors of this work.
|
|
.\" %%%LICENSE_END
|
|
.\"
|
|
.TH MALLOC_TRIM 3 2012-03-29 "Linux" "Linux Programmer's Manual"
|
|
.SH NAME
|
|
malloc_trim \- release free memory from the top of the heap
|
|
.SH SYNOPSIS
|
|
.B #include <malloc.h>
|
|
|
|
.BI "void malloc_trim(size_t " pad );
|
|
.SH DESCRIPTION
|
|
The
|
|
.BR malloc_trim ()
|
|
function attempts to release free memory at the top of the heap
|
|
(by calling
|
|
.BR sbrk (2)
|
|
with a suitable argument).
|
|
|
|
The
|
|
.I 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
|
|
.BR sbrk (2).
|
|
.SH RETURN VALUE
|
|
The
|
|
.BR 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.
|
|
.SH ERRORS
|
|
No errors are defined.
|
|
.\" .SH VERSIONS
|
|
.\" Available already in glibc 2.0, possibly earlier
|
|
.SH CONFORMING TO
|
|
This function is a GNU extension.
|
|
.SH NOTES
|
|
This function is automatically called by
|
|
.BR free (3)
|
|
in certain circumstances; see the discussion of
|
|
.B M_TOP_PAD
|
|
and
|
|
.B M_TRIM_THRESHOLD
|
|
in
|
|
.BR mallopt (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.
|
|
.\" malloc/malloc.c::mTRIm():
|
|
.\" return result | (av == &main_arena ? sYSTRIm (pad, av) : 0);
|
|
.SH SEE ALSO
|
|
.BR sbrk (2),
|
|
.BR malloc (3),
|
|
.BR mallopt (3)
|