Two TSocket instances in two threads will conflict?

ROOT
1

Hi,

I m trying to develop a root based application, which need two TSockets, each socket is responsible for receiving TMessages from a server, and when I put each socket in a separate thread it gives error (please see the following), but when I put it in a separate process it doesn’t!

The error message appears randomly, not immediately upon starting the run.

I guess two sockets running in the same process will conflict, what is the correct way to do it?

Can someone help?

Thanks a lot.

Bing

error info:
 *** Break *** segmentation violation
...
...........................
The lines below might hint at the cause of the crash.
You may get help by asking at the ROOT forum https://root.cern/forum
Only if you are really convinced it is a bug in ROOT then please submit a
report at https://root.cern/bugs Please post the ENTIRE stack trace
from above as an attachment in addition to anything else
that might help us fixing this issue.
......................................
#6  0x00007f1ee9fd56e4 in TClass::StreamerTObjectInitialized(TClass const*, void*, TBuffer&, TClass const*) () from /opt/root/lib/libCore.so.6.26
#7  0x00007f1ee91d2bef in TGenCollectionStreamer::WriteObjects(int, TBuffer&) () from /opt/root/lib/libRIO.so.6.26
#8  0x00007f1ee919f978 in TCollectionStreamer::Streamer(TBuffer&, void*, int, TClass*) () from /opt/root/lib/libRIO.so.6.26
#9  0x00007f1ee9147aeb in TBufferFile::WriteFastArray(void*, TClass const*, int, TMemberStreamer*) () from /opt/root/lib/libRIO.so.6.26
#10 0x00007f1ee93d71c4 in int TStreamerInfo::WriteBufferAux<char**>(TBuffer&, char** const&, TStreamerInfo::TCompInfo* const*, int, int, int, int, int) () from /opt/root/lib/libRIO.so.6.26
#11 0x00007f1ee9222ab4 in TStreamerInfoActions::GenericWriteAction(TBuffer&, void*, TStreamerInfoActions::TConfiguration const*) () from /opt/root/lib/libRIO.so.6.26
#12 0x00007f1ee914d6d5 in TBufferFile::WriteClassBuffer(TClass const*, void*) () from /opt/root/lib/libRIO.so.6.26
#13 0x00007f1ee906949f in RawEvent::Streamer (this=0x7f1ee3c6e960, R__b=...) at /storage/ATTPC/DAQ/build/src/RawEvent/RawEvent_dict.cxx:221
#14 0x00007f1ee914cdbb in TBufferFile::WriteObjectClass(void const*, TClass const*, bool) () from /opt/root/lib/libRIO.so.6.26
#15 0x00007f1ee91544cf in TBufferIO::WriteObjectAny(void const*, TClass const*, bool) () from /opt/root/lib/libRIO.so.6.26
#16 0x00007f1eea315680 in TBuffer::WriteObject<RawEvent> (this=0x7f1eab4e57b0, objptr=0x7f1ee3c6e960, cacheReuse=true) at /opt/root/include/TBuffer.h:414
#17 0x00007f1eea314224 in TMessageBufferTP<RawEvent>::put (this=0x7f1e81ea5390, obj=0x7f1ee3c6e960) at /usr/local/include/TMessageBufferTP.h:53
#18 0x00007f1eea310046 in DataProcessor::rawEventProcess (this=0x55ff6919b450, ptrArray=0x7f1ee3c6aad0, fileID=69) at /DAQ/src/DataProcessor/DataProcessor.cpp:239

_ROOT Version: 6.26/04
_Platform: 22.04.1-Ubuntu x86_64 GNU/Linux
_Compiler: c++ (Ubuntu 11.2.0-19ubuntu1) 11.2.0

2

Hello,

Welcome to the ROOT community! Thanks for posting your question.
Could you provide a minimal reproducer?

Cheers,
Danilo

3

Did you turn on thread support by calling:

ROOT::EnableThreadSafety();

?

4

DAQ_forRootDebug.zip (4.5 KB)

Hi Danilo,

Thanks!

The attached file is a minimal reproducer.

Regards,
Bing

5

I tried. But get different error.

6

What is the new error?

7

Dear Bing,

Thanks. I will get to this in 24 hours.

Cheers,
D

8

Great, the ROOT::EnableThreadSafety() make my code work. In my previous try, I put this function in a wrong place. Now, it works.

Thank you.

9

Hi Danilo,

With Ppcanal’s reminder, ROOT::EnableThreadSafety() solved the problem, thanks again!

Cheers,
Bing

1 Like
10

Sorry I was not clear:

  • ROOT::EnableThreadSafety() is compulsory to use ROOT code from multiple threads
  • It needs to be called before any threads is started.

Cheers,
Philippe.

1 Like
11

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