Re: [PATCH] winemp3.acm: Fixes compilation for older mpg123 library versions

[Sebastian Lackner]

On 19.02.2017 20:25, Bruno Jesus wrote:
> On Sun, Feb 19, 2017 at 4:04 PM, Bruno Jesus  wrote:
> > On Sun, Feb 19, 2017 at 3:57 PM, Sebastian Lackner  wrote:
> > > On 19.02.2017 19:54, Bruno Jesus wrote:
> > > > From: Bruno Jesus
> > > >
> > > > Fixes bug https://bugs.winehq.org/show_bug.cgi?id=42483
> > > > Signed-off-by: Bruno Jesus
> > > >
> > > > dlls/winemp3.acm/mpegl3.c | 2 ++
> > > >  1 file changed, 2 insertions(+)
> > > >
> > > > diff --git a/dlls/winemp3.acm/mpegl3.c b/dlls/winemp3.acm/mpegl3.c
> > > > index 28a1998..100aa49 100644
> > > > --- a/dlls/winemp3.acm/mpegl3.c
> > > > +++ b/dlls/winemp3.acm/mpegl3.c
> > > > @@ -249,12 +249,14 @@ static  LRESULT MPEG3_StreamOpen(PACMDRVSTREAMINSTANCE adsi)
> > > >          aad->mh = mpg123_new(NULL,&err);
> > > >          mpg123_open_feed(aad->mh);
> > > >
> > > > +#ifdef MPG123_IGNORE_INFOFRAME
> > >
> > > Are you sure this works? On my system it is an enum, not a define.
> >
> > You are absolutely right, it doesn't. I was a victim of my own "add error inside #ifdef/else and recompile test", probably recompiled before saving.
>
> Would you mind helping me understand why the check at [1] fails with:
>
> 14734 configure:13848: checking for MPG123_IGNORE_INFOFRAME
> 14735 configure:13848: ccache gcc-4.6 -m32 -c -g -O0   conftest.c >&5
> 14736 configure:13848: $? = 0
> 14737 configure:13848: ccache gcc-4.6 -m32 -c -g -O0   conftest.c >&5
> 14738 configure:13848: $? = 0
> 14739 configure:13848: result: no
>
> [1] http://pastebin.com/nveZQNDR
>
> I never did this sort of change before and the best example I found
> was some libxml2 stuff inside configure.ac.
>
> Thanks in advance,
> Bruno

Usually config.log also contains the code which was used for the check.
In this case, I would assume it fails because MPG123_IGNORE_INFOFRAME
isn't really a type. The type is "enum mpg123_param_flags", but testing
for that obviously doesn't make much sense.

I would suggest a slightly different solution. The commit where the
feature (including the MPG123_IGNORE_INFOFRAME const) was added is:

https://www.mpg123.de/cgi-bin/scm/mpg123?view=revision&revision=2910
https://www.mpg123.de/cgi-bin/scm/mpg123/trunk/src/libmpg123/mpg123.h.in?r1=...

As you can see, in the same commit the API_VERSION was bumped to 31.

https://www.mpg123.de/cgi-bin/scm/mpg123/trunk/configure.ac?r1=2910&r2=2...

So why not just something like:

#if MPG123_API_VERSION >= 31 /* needed for MPG123_IGNORE_FRAMEINFO */

Best regards,
Sebastian