TThread and c-function

ROOT
1

Hi,

I am trying to use TThread to run a c-function.

I used to do:

int Connect2TWS::ThreadStart( tws_func_t func, void *arg ) {
pthread_t thr ;
int err = pthread_create(&thr, 0, (void ()(void *)) func, arg) ;
return err ;
}

and replaced it with what I would naively expect to be correct:

int Connect2TWS::ThreadStart( tws_func_t func, void *arg ) {
TThread thr = new TThread( (void() (void *)) func, arg) ;
int err = thr->Run() ;
return err ;
}

In ROOT I now get:

root [2] bla->AddConnection()
tws reader thread started
tws reader thread terminated
root [3]

Instead of the previous:

root [2] bla->AddConnection()
tws reader thread started
root [3]

So, the TThread starts and stops immediately, where the pthread keeps on running. Am I missing something trivial? Under the hood, TThread is simply calling pthread, isn’t it?

Thanks for your assistance,
Sander Klous

2

Hi Sander,

this should work fine. What is hapening in your user function? Mail me an small example.

Cheers, Fons.

3

Hi Fons,

I attached the debugger to shed some light on this subject.
Apparently, if I put a breakpoint on any of the lines between

if (!ierr) th->fId = (Long_t) id ;

in TPosixThread.cxx and

SetComment() ;

in TThread.cxx, the code runs fine. Outside of this region, breakpoints have no effect whatsoever. Based on this observation, I doubt if I am able to provide a small example. For the moment I’ll move back to the pthread code…

Thanks,
Sander

4

Hoi Sander,

any change I can try to debug this in the complete program, or is that the whole of ATLAS?

– Fons

5

Hi,
I tried to reproduce this problem on linux, but all works fine there.
So probably it is a gcc-cygwin only problem…

Still strange that it doesn’t show up when I use pthread directly.
Thanks,
Sander

6

Hi Sander,

thanks for letting us know.

–Fons