[Slackbuilds-users] About vlc SBo

[c***@exemail.com.au]

Hello,
This email is to tell about a problem in building vlc and how it could
be worked around.
I was just updating a system here (x86_64 with multilib), running
SlackBuilds manually to rebuild some old packages and experienced a
problem with the binary vlc generated, which gave segfaults
systematically.
I tried to analyze the problem and found a piece of code inside
pulseaudio which calls shm_open() (which is supplied from librt.so).
Going further, I found that shm_open() tries to call __shm_directory()
and this function - which is inside libpthread.so - is not correct
linked for some reason. When the call is tried, the segfault
happens.
(yes, to find it I have to google a little; this article showed the
https://stackoverflow.com/questions/47905554/segmentation-fault-appears-when-i-use-shared-memory-only-from-statically-build-p)
I could find a way to work around it. The vlc binary, as it was built in
the machine, required libpthread.so but not librt.so (verified by
calling objdump -x vlc). I managed to add librt.so in the final link
(using SLKLDFLAGS="-lrt") and the resulting vlc added librt.so as a
"NEEDED" dependency. Installing the package, the problem was gone.
Of course this is not happening in the majority of the installations,
but as it happened here, it can happen anywhere.
As I don't post here frequently, let me thank you contributors for the
time devoted to the project.
Many thanks!
Luiz Carlos Ramos
São Paulo - Brazil
_______________________________________________
SlackBuilds-users mailing list
https://lists.slackbuilds.org/mailman/listinfo/slackbuilds-users
Archives - https://lists.slackbuilds.org/pipermail/slackbuilds-users/
FAQ - https://slackbuilds.org/faq/

Interesting. I’ll look into this some more when I’’m able to.

chris

_______________________________________________
SlackBuilds-users mailing list
SlackBuilds-***@slackbuilds.org
https://lists.slackbuilds.org/mailman/listinfo/slackbuilds-users
Archives - https://lists.slackbuilds.org/pipermail/slackbuilds-users/
FAQ - https://slackbuilds.org/faq/

[Christoph Willing]

Hello,
This email is to tell about a problem in building vlc and how it could
be worked around.
I was just updating a system here (x86_64 with multilib), running
SlackBuilds manually to rebuild some old packages and experienced a
problem with the binary vlc generated, which gave segfaults
systematically.
I tried to analyze the problem and found a piece of code inside
pulseaudio which calls shm_open() (which is supplied from librt.so).
Going further, I found that shm_open() tries to call __shm_directory()
and this function - which is inside libpthread.so - is not correct
linked for some reason. When the call is tried, the segfault
happens.
(yes, to find it I have to google a little; this article showed the
https://stackoverflow.com/questions/47905554/segmentation-fault-appears-when-i-use-shared-memory-only-from-statically-build-p)
I could find a way to work around it. The vlc binary, as it was built in
the machine, required libpthread.so but not librt.so (verified by
calling objdump -x vlc). I managed to add librt.so in the final link
(using SLKLDFLAGS="-lrt") and the resulting vlc added librt.so as a
"NEEDED" dependency. Installing the package, the problem was gone.
Of course this is not happening in the majority of the installations,
but as it happened here, it can happen anywhere.

Hi Luiz,

Thanks for diagnosing the problem and suggesting a fix. I've never seen
that problem myself but you're right that it could happen anywhere so
I've just pushed an update which sets SLKLDFLAGS="-lrt".

chris
_______________________________________________
SlackBuilds-users mailing list
SlackBuilds-***@slackbuilds.org
https://lists.slackbuilds.org/mailman/listinfo/slackbuilds-users
Archives - https://lists.slackbuilds.org/pipermail/slackbuilds-users/
FAQ - https://slackbuilds.org/faq/