.\" Copyright (c) 1980, 1991 Regents of the University of California.
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
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.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
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.\" 4. 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.
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" 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
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.\"
.\"     @(#)alloca.3	5.1 (Berkeley) 5/2/91
.\"
.\" Converted Mon Nov 29 11:05:55 1993 by Rik Faith <faith@cs.unc.edu>
.\" Modified Tue Oct 22 23:41:56 1996 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified 2002-07-17, aeb
.\" 2008-01-24, mtk:
.\"     Various rewrites and additions (notes on longjmp() and SIGSEGV).
.\"     Weaken warning against use of alloca() (as per Debian bug 461100).
.\"
.\" Japanese Version Copyright (c) 1996 Kentaro OGAWA
.\"         all rights reserved.
.\" Translated Sat, 13 Jul 1996 22:44:04 +0900
.\"         by Kentaro OGAWA <k_ogawa@oyna.cc.muroran-it.ac.jp>
.\" Updated & Modified Tue Oct 16 01:01:48 JST 2001
.\"         by Yuichi SATO <ysato@mail.sbvl.muroran-it.ac.jp>
.\" Updated & Modified Sat Aug 31 04:42:49 JST 2002 by Yuichi SATO
.\"
.TH ALLOCA 3 2008-01-24 "GNU" "Linux Programmer's Manual"
.SH ̾
alloca \- ưŪ˲Ƥ
.SH 
.B #include <alloca.h>
.sp
.BI "void *alloca(size_t " size );
.SH 
.BR alloca ()
ؿϡ
.I size
ХȤΰƽиΥåե졼˳դ롣
ΰŪΰϡ
.BR alloca ()
ƤӽФؿƽи֤Ȥ˼ưŪ˲롣
.SH ֤
.BR alloca ()
ؿϡդΰλϤޤؤݥ󥿤֤
դˤäƥåСեä
ץưƤʤ
.SH 
δؿ POSIX.1-2001 ˤϤʤ

32V, PWB, PWB.2, 3BSD, 4BSD 
.BR alloca ()
ؿо줷ڵ򤬤롣
4.3BSD ˤϡޥ˥奢ڡ롣
Linux ϡGNU ǤȤäƤ롣
δؿ POSIX.1-2001 ˤϤʤ
.SH 
.BR alloca ()
ؿϡȥѥ˰¸롣
ΥץꥱǤϡδؿȤ
.BR malloc (3)

.BR free (3)
Ȥ߹碌ƻȤä٤ƸΨ뤳ȤǤ롣
ξǤϡδؿȤȤǡ
.BR longjmp (3)

.BR siglongjmp (3)
ȤץꥱǤΥγñˤ뤳ȤǤ롣
ʳξǤϡδؿλѤϿ侩ʤ

.BR alloca ()
ˤƤ֤ϥåե졼फƤΤǡ
ؿ褬
.BR longjmp (3)

.BR siglongjmp (3)
θƤӽФˤꥸפˤϡ
Ƥ줿֤ϼưŪ˲롣

.BR alloca ()
dzƤ줿֤
.BR free (3)
褦Ȥ뤳ȤΤʤ褦ˡ
.SH 
.SS GNU ǤˤĤƤ
̾
.BR gcc (1)

.BR alloca ()
θƤӽФ򥤥饤󥳡ɤѴ롣
.IR "\-ansi" ,
.IR "\-std=c89" ,
.IR "\-std=c99" ,
.IR "\-fno\-builtin"
Τ줫Υץ󤬻ꤵ줿硢ѴϹԤʤ
(ޤ
.I <alloca.h>
Υ󥯥롼ɤԤʤ)
ǥեȤǤ glibc Ǥ
.I <stdlib.h>

.I <alloca.h>
򥤥󥯥롼ɤƤꡢˤϰʲιԤޤޤƤΤդ뤳ȡ
.nf

    #define alloca(size)   __builtin_alloca (size)

.fi
ȼǤ __builtin_alloca (size) ؿʷ̤ˤʤ롣
.LP
Υɤϥ饤󲽤ƤΤǡ
δؿΥɥ쥹ꡢ
¾Υ饤֥󥯤ưѹ뤳ȤϤǤʤ
.LP
̾盧Υ饤󥳡ɤϥåݥ󥿤ư
1 Ĥ̿ (instruction) 鹽Ƥꡢ
åСեåʤ
ä NULL 顼֤뤳ȤϤʤ
.SH Х
åե졼बĥǤʤä硢顼ΤϹԤʤ
(ʤ顢Ƥ˼ԤǡץबƤʤä
֤˥褦Ȥ
.B SIGSEGV
ʥ뤳Ȥ)

¿ΥƥˤơؿΰΥꥹǤ
.BR alloca ()
Ȥʤ
ϡ
.BR alloca ()
ˤäͽ󤵤륹åΰ褬
ؿ˻Ȥ륹åΰ˸ƤޤǤ롣
.SH Ϣ
.BR brk (2),
.BR longjmp (3),
.BR malloc (3)