blob: eb62e0e7a52f16787cd5ac5084def332d5874aed [file] [log] [blame]
# alloca.m4 serial 7
dnl Copyright (C) 2002-2004, 2006 Free Software Foundation, 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],
[
dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
AC_REQUIRE([AC_PROG_CPP])
AC_REQUIRE([AC_PROG_EGREP])
AC_REQUIRE([AC_FUNC_ALLOCA])
if test $ac_cv_func_alloca_works = no; then
gl_PREREQ_ALLOCA
fi
# Define an additional variable used in the Makefile substitution.
if test $ac_cv_working_alloca_h = yes; then
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
#endif
], [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.
# STACK_DIRECTION is already handled by AC_FUNC_ALLOCA.
AC_DEFUN([gl_PREREQ_ALLOCA], [:])