[Freeciv-Dev] Re: (PR#2873) 1.14.0 Xaw client crash

["Stepan Roh via RT" <rt@xxxxxxxxxxxxxx>]

On Sun, 26 Jan 2003, Jason Short via RT wrote:

> Stepan Roh via RT wrote:
>
> > Quote (important part highlighted with >>><<<):
> >
> > "In order to do its job, autoheader needs you to document all of the
> > symbols that you might use; i.e., there must be at least one AC_DEFINE or
> > one AC_DEFINE_UNQUOTED call with a third argument for each symbol (see
> > section 7.1 Defining C Preprocessor Symbols). An additional constraint is
> > that the first argument of AC_DEFINE must be a >>>literal<<<. Note that
> > all symbols defined by Autoconf's builtin tests are already documented
> > properly; you only need to document those that you define yourself."
> >
> > I think it's obvious that you can't call AC_DEFINE with variable and
> > expect autoheader to trace it. It would be hard work to do it actually and
> > only with additional constraints (variable content may be based on runtime
> > state in which case it can't be computed before running) or syntactic
> > sugar.  AC_DEFINE works with variables (just add manually #undef
> > HAVE_LIBXAW3D to end of config.h.in and run ./configure
> > --enable-client=xaw3d and see that config.h contains #define HAVE_LIBXAW3D
> > 1). So it is not bug and it can't be changed.
>
> Read it again.  AC_DEFINE is not able to work with variables in the
> first position.  AC_DEFINE_UNQUOTED is.  It also says this under the
> node on AC_DEFINE/AC_DEFINE_UNQUOTED.

Hm, you're right.

> Since we use AC_DEFINE_UNQUOTED here, it *should* work.  But, well, it
> doesn't.

It can't be done. But they should document it clearly.

> Note that all we really need to do is put AC_DEFINE(HAVE_LIBXAW3D, ...)
> *somewhere* in our autoconf code.  It doesn't actually have to be
> called.  Then we get autoheader to work and everything is great.
>
> Alternately, we can hard-code the different values in FC_CHECK_X_LIB.
> Something like
>
> if $ac_tr_lib = "HAVE_LIBXAW3D"; then
>    AC_DEFINE_UNQUOTED(HAVE_LIBXAW3D, ...)
> else if $ac_tr_lib = "HAVE_LIBXAW"; then
>    ...
> ...
> fi

Definitely worst idea.

> Or we could put these values outside of the FC_CHECK_X_LIB call, i.e.
>
>    FC_CHECK_X_LIB(Xaw3d, main,
>                   AC_DEFINE_UNQUOTED(HAVE_LIBXAW3D, ...),
>                   AC_MSG_ERROR(did not find Xaw3d library))
>
> The question at this point is which is the least hack.  Seems to me the
> third method is (AFAICT this is what you are suggesting).

Now I suggest my script which is the least hack. Or my previous suggestion
which is your third method.

Stepan Roh