tor/m4/ax_check_sign.m4
Nick Mathewson 0e597471af Use a nicely written autoconf macro to determine the sign of a type
This beats our old implementation, which wouldn't work when cross-compiling
2013-02-07 16:23:48 -05:00

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# ===========================================================================
# http://www.gnu.org/software/autoconf-archive/ax_check_sign.html
# ===========================================================================
#
# SYNOPSIS
#
# AX_CHECK_SIGN (TYPE, [ACTION-IF-SIGNED], [ACTION-IF-UNSIGNED], [INCLUDES])
#
# DESCRIPTION
#
# Checks whether TYPE is signed or not. If no INCLUDES are specified, the
# default includes are used. If ACTION-IF-SIGNED is given, it is
# additional shell code to execute when the type is signed. If
# ACTION-IF-UNSIGNED is given, it is executed when the type is unsigned.
#
# This macro assumes that the type exists. Therefore the existence of the
# type should be checked before calling this macro. For example:
#
# AC_CHECK_HEADERS([wchar.h])
# AC_CHECK_TYPE([wchar_t],,[ AC_MSG_ERROR([Type wchar_t not found.]) ])
# AX_CHECK_SIGN([wchar_t],
# [ AC_DEFINE(WCHAR_T_SIGNED, 1, [Define if wchar_t is signed]) ],
# [ AC_DEFINE(WCHAR_T_UNSIGNED, 1, [Define if wchar_t is unsigned]) ], [
# #ifdef HAVE_WCHAR_H
# #include <wchar.h>
# #endif
# ])
#
# LICENSE
#
# Copyright (c) 2008 Ville Laurikari <vl@iki.fi>
#
# Copying and distribution of this file, with or without modification, are
# permitted in any medium without royalty provided the copyright notice
# and this notice are preserved. This file is offered as-is, without any
# warranty.
#serial 6
AU_ALIAS([VL_CHECK_SIGN], [AX_CHECK_SIGN])
AC_DEFUN([AX_CHECK_SIGN], [
typename=`echo $1 | sed "s/@<:@^a-zA-Z0-9_@:>@/_/g"`
AC_CACHE_CHECK([whether $1 is signed], ax_cv_decl_${typename}_signed, [
AC_TRY_COMPILE([$4],
[ int foo @<:@ 1 - 2 * !((($1) -1) < 0) @:>@ ],
[ eval "ax_cv_decl_${typename}_signed=\"yes\"" ],
[ eval "ax_cv_decl_${typename}_signed=\"no\"" ])])
symbolname=`echo $1 | sed "s/@<:@^a-zA-Z0-9_@:>@/_/g" | tr "a-z" "A-Z"`
if eval "test \"\${ax_cv_decl_${typename}_signed}\" = \"yes\""; then
$2
elif eval "test \"\${ax_cv_decl_${typename}_signed}\" = \"no\""; then
$3
fi
])dnl