Re: [Mingw-users] libtool, dlls and -lm

[Ralf Wildenhues]

[ adding subscribers-only mingw-users back -- they may have useful
input on this ] 

Hi Bob, 

* Bob Friesenhahn wrote on Mon, Dec 19, 2005 at 06:46:21PM CET:
> On Mon, 19 Dec 2005, Ralf Wildenhues wrote:
> >
> >Question to libtool folks: OK to apply this patch? 
>
> There are other reasons not to find the 'file' command.  For example, 
> it does not appear to be provided with the MSYS environment.  But 
> objdump is provided with MinGW.  That is why I had MinGW using objdump 
> while Cygwin uses file.

Sure. 

> The patch assumes particular output from the 'file' command.

It assumes that, for an ar archive, it will output something matching
*ar\ archive*
(in shell pattern notation). 

I believe that is fairly safe; I've even tested that now on some BSDs.
Note func_win32_libid uses `$OBJDUMP -f' and `$NM -f posix -A ..'
to determine whether it's an import library.  Both of those tools have
to be part of the cross-toolchain on non-mingw, so that should be safe
as well.  Besides, if my patch introduced brokenness for cross-compiles,
that would already be broken for any cross-compile to cygwin anyway. 

> Since there is no standard 'file' command provided with MSYS/MinGW, is
> this safe?

OK, so the only remaining case really is MSYS/MinGW itself.  Do we know
of win32 installations that provide a `file' command that does not do
what we expect?  Note that not having `file' available would be fine
here, but one that does something completely unrelated, for example,
would hurt. 

Maybe we should limit use of func_win32_libid to the case where both
`file' is available and $host != $build? 

> What if MinGW is used in a cross-development environment (e.g.  some
> *BSD environment) which uses a different 'file' program than expected?

See above: that should be safe. 

Any more issues? 

Cheers,
Ralf 

> >       * libtool.m4 (AC_DEPLIBS_CHECK_METHOD) [ mingw, pw32 ]:
> >       If `file' is present, use `func_win32_libid' rather than
> >       `objdump -f', to facilitate cross-compilation.
> >       Reported by Pierre Ossman <address@hidden>.