2 dnl Copyright (C) 2002-2004, 2006-2007, 2009-2010 Free Software Foundation,
4 dnl This file is free software; the Free Software Foundation
5 dnl gives unlimited permission to copy and/or distribute it,
6 dnl with or without modifications, as long as this notice is preserved.
8 AC_DEFUN([gl_FUNC_ALLOCA],
10 dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
11 AC_REQUIRE([AC_PROG_CPP])
12 AC_REQUIRE([AC_PROG_EGREP])
14 AC_REQUIRE([AC_FUNC_ALLOCA])
15 if test $ac_cv_func_alloca_works = no; then
19 # Define an additional variable used in the Makefile substitution.
20 if test $ac_cv_working_alloca_h = yes; then
21 AC_CACHE_CHECK([for alloca as a compiler built-in], [gl_cv_rpl_alloca], [
22 AC_EGREP_CPP([Need own alloca], [
23 #if defined __GNUC__ || defined _AIX || defined _MSC_VER
26 ], [gl_cv_rpl_alloca=yes], [gl_cv_rpl_alloca=no])
28 if test $gl_cv_rpl_alloca = yes; then
29 dnl OK, alloca can be implemented through a compiler built-in.
30 AC_DEFINE([HAVE_ALLOCA], [1],
31 [Define to 1 if you have 'alloca' after including <alloca.h>,
32 a header that may be supplied by this distribution.])
35 dnl alloca exists as a library function, i.e. it is slow and probably
36 dnl a memory leak. Don't define HAVE_ALLOCA in this case.
45 # Prerequisites of lib/alloca.c.
46 # STACK_DIRECTION is already handled by AC_FUNC_ALLOCA.
47 AC_DEFUN([gl_PREREQ_ALLOCA], [:])