-# alloca.m4 serial 4
-dnl Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
-dnl This file is free software, distributed under the terms of the GNU
-dnl General Public License. As a special exception to the GNU General
-dnl Public License, this file may be distributed as part of a program
-dnl that contains a configuration script generated by Autoconf, under
-dnl the same distribution terms as the rest of that program.
+# alloca.m4 serial 9
+dnl Copyright (C) 2002-2004, 2006-2007, 2009-2010 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_ALLOCA],
[
# Define an additional variable used in the Makefile substitution.
if test $ac_cv_working_alloca_h = yes; then
- AC_EGREP_CPP([Need own alloca], [
+ AC_CACHE_CHECK([for alloca as a compiler built-in], [gl_cv_rpl_alloca], [
+ AC_EGREP_CPP([Need own alloca], [
#if defined __GNUC__ || defined _AIX || defined _MSC_VER
- Need own alloca
+ Need own alloca
#endif
- ],
- [AC_DEFINE(HAVE_ALLOCA, 1,
- [Define to 1 if you have `alloca' after including <alloca.h>,
- a header that may be supplied by this distribution.])
- ALLOCA_H=alloca.h],
- [ALLOCA_H=])
+ ], [gl_cv_rpl_alloca=yes], [gl_cv_rpl_alloca=no])
+ ])
+ if test $gl_cv_rpl_alloca = yes; then
+ dnl OK, alloca can be implemented through a compiler built-in.
+ AC_DEFINE([HAVE_ALLOCA], [1],
+ [Define to 1 if you have 'alloca' after including <alloca.h>,
+ a header that may be supplied by this distribution.])
+ ALLOCA_H=alloca.h
+ else
+ dnl alloca exists as a library function, i.e. it is slow and probably
+ dnl a memory leak. Don't define HAVE_ALLOCA in this case.
+ ALLOCA_H=
+ fi
else
ALLOCA_H=alloca.h
fi
AC_SUBST([ALLOCA_H])
-
- AC_DEFINE(HAVE_ALLOCA_H, 1,
- [Define HAVE_ALLOCA_H for backward compatibility with older code
- that includes <alloca.h> only if HAVE_ALLOCA_H is defined.])
])
# Prerequisites of lib/alloca.c.