shithub: aacdec

ref: 1a8846b50eb297b9faa06e1273b1589a7ee833ca
dir: /common/id3lib/m4/lf_cxx.m4/

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dnl Autoconf support for C++
dnl Copyright (C) 1988 Eleftherios Gkioulekas <[email protected]>
dnl  
dnl This program is free software; you can redistribute it and/or modify
dnl it under the terms of the GNU General Public License as published by
dnl the Free Software Foundation; either version 2 of the License, or
dnl (at your option) any later version.
dnl 
dnl This program is distributed in the hope that it will be useful,
dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
dnl GNU General Public License for more details.
dnl 
dnl You should have received a copy of the GNU General Public License
dnl along with this program; if not, write to the Free Software 
dnl Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
dnl 
dnl As a special exception to the GNU General Public License, if you 
dnl distribute this file as part of a program that contains a configuration 
dnl script generated by Autoconf, you may include it under the same 
dnl distribution terms that you use for the rest of that program.

# -----------------------------------------------------------------
# This macro should be called to configure your C++ compiler.
# When called, the macro does the following things:
# 1. It finds an appropriate C++ compiler
#    If you passed the flag --with-cxx=foo, then it uses that
#    particular compiler
# 2. Checks whether the compiler accepts the -g 
# ------------------------------------------------------------------

AC_DEFUN(LF_CONFIGURE_CXX,[
 AC_PROG_CXX 
 AC_PROG_CXXCPP
 LF_CXX_PORTABILITY
])

# -----------------------------------------------------------------------
# This macro tests the C++ compiler for various portability problem.
# 1. Defines CXX_HAS_NO_BOOL if the compiler does not support the bool
#    data type
# 2. Defines CXX_HAS_BUGGY_FOR_LOOPS if the compiler has buggy
#    scoping for the for-loop
# Seperately we provide some config.h.bot code to be added to acconfig.h
# that implements work-arounds for these problems.
# -----------------------------------------------------------------------

dnl ACCONFIG TEMPLATE
dnl #undef CXX_HAS_BUGGY_FOR_LOOPS
dnl #undef CXX_HAS_NO_BOOL
dnl END ACCONFIG

AC_DEFUN(LF_CXX_PORTABILITY,[

  AC_PROVIDE([$0])

  dnl
  dnl Check for common C++ portability problems
  dnl

  AC_LANG_SAVE
  AC_LANG_CPLUSPLUS

  dnl Check whether we have bool
  AC_MSG_CHECKING(whether C++ has bool)
  AC_TRY_RUN([main() { bool b1=true; bool b2=false; }],
             [ AC_MSG_RESULT(yes) ],
             [ AC_MSG_RESULT(no)
               AC_DEFINE(CXX_HAS_NO_BOOL) ],
             [ AC_MSG_WARN(Don't cross-compile)]
            )

  dnl Test whether C++ has buggy for-loops
  AC_MSG_CHECKING(whether C++ has correct scoping in for-loops)
  AC_TRY_COMPILE([#include <iostream.h>], [
   for (int i=0;i<10;i++) { }
   for (int i=0;i<10;i++) { }
], [ AC_MSG_RESULT(yes) ],
   [ AC_MSG_RESULT(no)
     AC_DEFINE(CXX_HAS_BUGGY_FOR_LOOPS) ])

  dnl Done with the portability checks
  AC_LANG_RESTORE
])

dnl ACCONFIG BOTTOM
dnl 
dnl // This file defines portability work-arounds for various proprietory
dnl // C++ compilers
dnl 
dnl // Workaround for compilers with buggy for-loop scoping
dnl // That's quite a few compilers actually including recent versions of
dnl // Dec Alpha cxx, HP-UX CC and SGI CC.
dnl // The trivial "if" statement provides the correct scoping to the 
dnl // for loop
dnl 
dnl #ifdef CXX_HAS_BUGGY_FOR_LOOPS
dnl #undef for
dnl #define for if(1) for
dnl #endif
dnl 
dnl //
dnl // If the C++ compiler we use doesn't have bool, then
dnl // the following is a near-perfect work-around. 
dnl // You must make sure your code does not depend on "int" and "bool"
dnl // being two different types, in overloading for instance.
dnl //
dnl 
dnl #ifdef CXX_HAS_NO_BOOL
dnl #define bool int
dnl #define true 1
dnl #define false 0
dnl #endif
dnl    
dnl END ACCONFIG