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diff --git a/man3/alloca.3 b/man3/alloca.3 new file mode 100644 index 000000000..b88ad123c --- /dev/null +++ b/man3/alloca.3 @@ -0,0 +1,107 @@ +.\" Copyright (c) 1980, 1991 Regents of the University of California. +.\" 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. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by the University of +.\" California, Berkeley and its contributors. +.\" 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. +.\" +.\" 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. +.\" +.\" @(#)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 +.\" +.TH ALLOCA 3 2002-07-17 "GNU" "Linux Programmer's Manual" +.SH NAME +alloca \- memory allocator +.SH SYNOPSIS +.B #include <alloca.h> +.sp +.BI "void *alloca(size_t " size ); +.SH DESCRIPTION +The +.B alloca +function allocates +.I size +bytes of space in the stack frame of the caller. This temporary space is +automatically freed when the function that called +.B alloca +returns to its caller. +.SH "RETURN VALUE" +The +.B alloca +function returns a pointer to the beginning of the allocated space. +If the allocation causes stack overflow, program behaviour is undefined. +.SH "CONFORMING TO" +There is evidence that the +.B alloca +function appeared in 32v, pwb, pwb.2, 3bsd, and 4bsd. There is a man page +for it in BSD 4.3. Linux uses the GNU version. +This function is not in POSIX or SUSv3. +.SH "NOTES ON THE GNU VERSION" +Normally, +.B gcc +translates calls to +.B alloca +by inlined code. This is not done when either the \-ansi or +the \-fno\-builtin option is given. But beware! By default +the glibc version of +.I <stdlib.h> +includes +.I <alloca.h> +and that contains the line +.RS +# define alloca(size) __builtin_alloca (size) +.RE +with messy consequences if one has a private version of this function. +.LP +The fact that the code is inlined, means that it is impossible +to take the address of this function, or to change its behaviour +by linking with a different library. +.LP +The inlined code often consists of a single instruction adjusting +the stack pointer, and does not check for stack overflow. +Thus, there is no NULL error return. +.SH BUGS +The +.B alloca +function is machine and compiler dependent. On many systems +its implementation is buggy. Its use is discouraged. +.LP +On many systems +.B alloca +cannot be used inside the list of arguments of a function call, because +the stack space reserved by +.B alloca +would appear on the stack in the middle of the space for the +function arguments. +.SH "SEE ALSO" +.BR brk (2), +.BR pagesize (2), +.BR calloc (3), +.BR malloc (3), +.BR realloc (3) |