Re: [PATCH] Serious problem with Autoconf on RedHat 7

[Morten Eriksen]

Akim Demaille <address@hidden> writes:

> | Index: aclang.m4
> | ===================================================================
> | RCS file: /cvs/autoconf/aclang.m4,v
> | retrieving revision 1.68
> | diff -u -r1.68 aclang.m4
> | --- aclang.m4       2000/10/02 13:11:28     1.68
> | +++ aclang.m4       2000/10/02 17:19:28
> | @@ -412,9 +412,6 @@
> |  define([AC_LANG_SOURCE(C++)],
> |  [#line __oline__ "configure"
> |  #include "confdefs.h"
> | -#ifdef __cplusplus
> | -extern "C" void exit (int);
> | -#endif
> |  $1])
> 
> I'm in favor of this patch given that it applies only to C++.  Note
> however, that it does not solve the problem for people who use
> CC=g++.

Are you sure there _is_ a problem when using CC=g++? I'm at least not
seeing any with this configure.in:

AC_INIT(configure.in)
AC_LANG_C
AC_TRY_COMPILE([#include <stdlib.h>], [], , AC_MSG_ERROR(sorr-ee))
AC_OUTPUT()

..and configure run like this:

  $ ./configure CC=g++

Which shouldn't be any surprise, as AC_LANG_SOURCE(C) does not add any
explicit exit() declaration, like AC_LANG_SOURCE(C++) does.

It'd be interesting to know what the ``extern "C" void exit (int);''
was doing there in the first place..?

BTW, the ``#ifdef __cplusplus'' also looks strange, given that the
macro name AC_LANG_SOURCE(C++) seems to assert that we are always
using a C++ compiler to compile the generated source file?

Regards,
Morten