Ah, we're making progress; thank you! This is the first I've heard
that "AC_LANG_PROGRAM supports the use of exit() in C/C++ program test
fragments" -- I haven't found any documentation to this effect. Does
anyone know the rationale for this decision? If so, let's please
ensure it's written down somewhere.
More to the point: Assuming this feature is indeed an autoconf
requirement, could its logic be encapsulated so that test programs
that want or need to call exit() can enable this feature? I can
imagine, for example, requiring such a test program to contain the
equivalent of:
#define I_NEED_TO_CALL_EXIT
so that <confdefs.h> could be expressed:
#if defined(__cplusplus) && defined(I_NEED_TO_CALL_EXIT)
#include <stdlib.h>
#endif
Perhaps negative logic would be preferable for reasons of backward
compatibility:
#if defined(__cplusplus) && ! defined(I_DONT_NEED_TO_CALL_EXIT)
#include <stdlib.h>
#endif
I could adapt to either.
In any case, I can't live with the status quo, since even my little
tests require complete control over headers that are included. (Since
the search paths in our environment are non-standard, all of my little
tests are innocently being given the wrong <stdlib.h> -- when they
really don't need any such header! The suggested alternative
involving <cstdlib> seems reasonable, but really doesn't change the
situation for me.) For now, I guess I'm going to avoid <confdefs.h>
and try to write my actions so as to produce my own equivalent to
<confdefs.h> -- does this seem feasible?
Thanks again.
- WEB
----- Original Message -----
From: "Raja R Harinath" <[EMAIL PROTECTED]>
To: "Paul Eggert" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]>
Sent: Friday, July 05, 2002 3:31 PM
Subject: Re: Contents of <confdefs.h> for C++
> Hi,
>
> Paul Eggert <[EMAIL PROTECTED]> writes:
>
> >> Date: Fri, 05 Jul 2002 10:40:17 -0500
> >> From: "Walter E. Brown" <[EMAIL PROTECTED]>
> >>
> >> Thanks, Paul, for the courteous and quick response.
> >>
> >> Suppose my program defines entities whose names clash with names
> >> declared in <stdlib.h>.
> >
> > That's certainly reasonable, but we're not talking about your
actual
> > program here. We're talking about what the little test program --
the
> > one that "configure" compiles. Surely this little test program
can be
> > written so that it will still work as desired even if <stdlib.h>
is
> > included.
>
> Yep. The program itself will/should never see 'confdefs.h', which
> should be deleted once 'configure' is done.
>
> Also, any fragment in 'configure.in' is basically testing for
> portability (and/or lack of portability :-) -- so it must be quite
> tolerant (or quite intolerant so that problems are found quickly).
>
> >> However, there may be compelling reasons for autoconf's current
> >> behavior
> >
> > If you find them out, please let me know. Like I said, I don't
use
> > C++, so I'm not the right guy to ask. It would be helpful if this
> > stuff were written down as comments in the source.
>
> I guess the loop in _AC_PROG_CXX_EXIT_DECLARATION
>
> for ac_declaration in \
> ''\
> '#include <stdlib.h>' \
> 'extern "C" void std::exit (int) throw (); using std::exit;' \
> 'extern "C" void std::exit (int); using std::exit;' \
> 'extern "C" void exit (int) throw ();' \
> 'extern "C" void exit (int);' \
> 'void exit (int);'
>
> could use one more alternative:
>
> '#include <cstdlib>
> using std::exit;'
>
> before the '#include <stdlib.h>' line.
>
> This whole section is necessary since AC_LANG_PROGRAM supports the
> use of exit() in C/C++ program test fragments.
>
> - Hari
> --
> Raja R Harinath ------------------------------ [EMAIL PROTECTED]
>
