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Add new man page for reallocarray(3)

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Import man page from OpenBSD.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=85622
This commit is contained in:
Guillem Jover 2014-10-31 17:29:54 +01:00
parent 02b55488c5
commit a6fe103c1b
2 changed files with 103 additions and 0 deletions
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1
man/Makefile.am
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@ -42,6 +42,7 @@ dist_man_MANS = \
queue.3bsd \
radixsort.3 \
readpassphrase.3 \
reallocarray.3 \
reallocf.3 \
setmode.3 \
setproctitle.3 \

102
man/reallocarray.3 Normal file
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@ -0,0 +1,102 @@
.\"
.\" Copyright (c) 1980, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the American National Standards Committee X3, on Information
.\" Processing Systems.
.\"
.\" 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.
.\" 3. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $OpenBSD: malloc.3,v 1.78 2014/05/01 18:41:59 jmc Exp $
.\"
.Dd $Mdocdate: May 1 2014 $
.Dt MALLOC 3
.Os
.Sh NAME
.Nm reallocarray
.Nd memory allocation and deallocation
.Sh LIBRARY
.ds str-Lb-libbsd Utility functions from BSD systems (libbsd, \-lbsd)
.Lb libbsd
.Sh SYNOPSIS
.In bsd/stdlib.h
.Ft void *
.Fn reallocarray "void *ptr" "size_t nmemb" "size_t size"
.Sh DESCRIPTION
.Pp
When using
.Fn malloc
be careful to avoid the following idiom:
.Bd -literal -offset indent
if ((p = malloc(num * size)) == NULL)
err(1, "malloc");
.Ed
.Pp
The multiplication may lead to an integer overflow, which can
be avoided using the extension
.Fn reallocarray ,
as follows:
.Bd -literal -offset indent
if ((p = reallocarray(NULL, num, size)) == NULL)
err(1, "malloc");
.Ed
.Pp
Alternatively
.Fn calloc
is a more portable solution which comes with the cost of clearing memory.
.Pp
If
.Fn malloc
must be used, be sure to test for overflow:
.Bd -literal -offset indent
if (size && num > SIZE_MAX / size) {
errno = ENOMEM;
err(1, "overflow");
}
.Ed
.Pp
The use of
.Fn reallocarray
or
.Fn calloc
is strongly encouraged when allocating multiple sized objects
in order to avoid possible integer overflows.
.Sh RETURN VALUES
The
.Fn reallocarray
function returns a pointer to the allocated space if successful; otherwise,
a null pointer is returned and
.Va errno
is set to
.Er ENOMEM .
.Sh SEE ALSO
.Xr malloc 3 ,
.Xr calloc 3 ,
.Xr alloca 3
.Sh HISTORY
.Fn reallocarray
appeared in
.Ox 5.6 .