[FFmpeg-devel] Why 'You can only build one library type at once on MinGW'?

[Michael Niedermayer]

Hi

On Sat, May 12, 2007 at 03:13:00AM +0300, Uoti Urpala wrote:
> On Sat, 2007-05-12 at 01:15 +0200, Michael Niedermayer wrote:
> > and to get this totally off topic disscussion a little back to ffmpeg, 
> > i wish i could get gcc to make all symbols which arent in a specific set
> > of headers "library-wide static" anyone knows a simple and clean trick
> > to do that?
> 
> "-fvisibility=hidden" makes all symbol definitions generated hidden by
> default, so that they do not appear in the external API. You can
> explicitly mark some as public by using
> '__attribute__((visibility("default")))', or using a #pragma to change
> the default for some part of a file.
> 
> That takes care of the visibility of generated symbols and thus of the
> external API part. However it's not enough for the code efficiency part.
> Because the code will include external headers too -fvisibility can not
> change the default for extern symbol _declarations_ (otherwise symbols
> declared within say "#include <stdlib.h>" would be assumed to be in the
> same library). So to make the code access symbols defined in other files
> of the same library more efficiently you need to mark the visibility in
> internal headers too to distinguish them from headers declaring symbols
> that will be in external libraries. Again you can do this by either
> using a per-symbol attribute or using a #pragma (the #pragma changes the
> default for both definitions and extern declarations).

so simply adding a #pragma at the begin and end of all internal headers
would make them hidden from outside and avoid the silly double indirection
when they are accessed?

if so, patch welcome

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus
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