[Slackbuilds-users] Jack-rack make failure

x80 x80 at telus.net
Wed Mar 14 17:54:00 UTC 2018

On 03/13/2018 02:54 PM, B Watson wrote:
> On 3/13/18, x80 <x80 at telus.net> wrote:
>> Yes it's jack2.
>> The Libs line in jack.pc looks like this:
>> Libs: -L/usr/lib64 -ljack
>> Seems it wasn't compiled with pthreads. I wonder if it's not a corrupt lib?
> Eh, it probably isn't "corrupt", it's probably just that jack-rack
> expects the .pc file for the jack library to always include -lpthread,
> so doesn't include -lpthread explicitly.
> You can use ldd on the jack library to find out whether or not it was
> compiled with pthreads (I suspect it was), but whether or not jack2 was
> built with pthreads, jack-rack has to be.
ldd /usr/bin/jackd returns that it was built against libpthread.
> In jack-rack.SlackBuild, the configure command reads:
> LDFLAGS="-lm -ldl" \
> ./configure \
>    --prefix=/usr \
>    --libdir=/usr/lib${LIBDIRSUFFIX} \
>    --sysconfdir=/etc \
>    --localstatedir=/var \
>    --mandir=/usr/man \
>    $LASH_OPT \
>    --disable-gnome \
>    --build=$ARCH-slackware-linux
> Change the first line of that to read:
> LDFLAGS="-lm -ldl -lpthread" \
> ...don't forget the trailing backslash!
I'll do a reinstall with the above changes later today.
> Let me know whether or not that fixes the problem... and even if it
> fixes this specific issue, there may be others.
> If that fixes it, I'll probably just patch jack2's .pc file to include
> -lpthread, since I suspect lots of other jack apps will have the same
> problem when built with jack2.
> Basically, jack2 on SBo is almost completely untested. Someone
> submitted it a few years back and never updated it, and none of the
> READMEs for any of the JACK-related stuff mentions it. They all list
> jack-audio-connection-kit (AKA jack1) as a dependency in their .info
> files, so that's what people end up using.
Jack2 is the optional dependency for qjackctl. Maybe I'll remove jack2 
and reinstall jack1.
I see alsa is routed to pulseaudio in /etc/asound.conf. That scares me. 
I was content with only alsa.
> You're the first user I've met who has even tried jack2, so I'm very
> interested to know what you've done with it. What SBo JACK stuff have
> you installed, and how well do they work, that sort of thing.
I use ffmpeg, mplayer/mencoder for video and audio repair and 
conversion. Also Blender. The idea with jack was to enable midi and a 
sequencer so I could do my own soundtracks and effects on home produced 
short films.

So, Version modified SBo's for required libs and includes, manual builds 
for the software I use.

The Jack stuff I've built with SBo's include jack-keyboard, qjackctl 
built against qt5 (mfw HUGE!) and alsa-plugin-jack.

I do have an unrelated day job, but I could be made available for some 
SBo testing if you need it.

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