minix/lib/libc/sys/mremap.2
Lionel Sambuc f14fb60209 Libraries updates and cleanup
* Updating common/lib
 * Updating lib/csu
 * Updating lib/libc
 * Updating libexec/ld.elf_so
 * Corrected test on __minix in featuretest to actually follow the
   meaning of the comment.
 * Cleaned up _REENTRANT-related defintions.
 * Disabled -D_REENTRANT for libfetch
 * Removing some unneeded __NBSD_LIBC defines and tests

Change-Id: Ic1394baef74d11b9f86b312f5ff4bbc3cbf72ce2
2013-01-14 11:36:26 +01:00

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.\" $NetBSD: mremap.2,v 1.4 2011/04/28 12:00:55 wiz Exp $
.\"
.\" Copyright (c) 2007 Thomas Klausner and Joerg Sonnenberger
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\"
.\" ------------------------------------------------------------
.Dd February 14, 2008
.Dt MREMAP 2
.Os
.Sh NAME
.Nm mremap
.Nd re-map a virtual memory address
.\" ------------------------------------------------------------
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/mman.h
.Ft void *
.Fn mremap "void *oldp" "size_t oldsize" "void *newp" "size_t newsize" \
"int flags"
.\" ------------------------------------------------------------
.Sh DESCRIPTION
The
.Fn mremap
function resizes the mapped range (see
.Xr mmap 2 )
starting at
.Ar oldp
and having size
.Ar oldsize
to
.Ar newsize .
The following arguments can be
.Dv OR Ap ed
together in the
.Ar flags
argument:
.Bl -tag -width XXMAPXALIGNEDXnXX
.It Dv MAP_ALIGNED Ns Pq Ar n
The allocation should be aligned to the given boundary, i.e. ensure
that the lowest
.Ar n
bits of the address are zero.
The parameter
.Ar n
should be the base 2 logarithm of the desired alignment (e.g., to
request alignment to 16K, use 14 as the value for n).
The alignment must be equal to or greater than the platform's page
size as returned by
.Xr sysconf 3
with the
.Dv _SC_PAGESIZE
request.
.It Dv MAP_FIXED
.Ar newp
is tried and
.Fn mremap
fails if that address can't be used as new base address for the range.
Otherwise,
.Ar oldp
and
.Ar newp
are used as hints for the position, factoring in the given alignment.
.El
.Sh RETURN VALUES
.Fn mremap
returns the new address or
.Dv MAP_FAILED ,
if the remap failed.
.Sh COMPATIBILITY
The semantics of
.Fn mremap
differ from the one provided by glibc on Linux in that the
.Ar newp
argument was added and a different set of
.Ar flags
are implemented.
.Sh SEE ALSO
.Xr mmap 2 ,
.Xr munmap 2
.Sh HISTORY
The
.Fn mremap
system call appeared in
.Nx 5.0 .
It was based on the code that supports
.Fn mremap
compatibility for Linux binaries.