pthread's mutex question

[Pattara Kiatisevi]

On Mon, 29 Apr 2002, Joel Sherrill wrote:

>
>
> Pattara Kiatisevi wrote:
> >
> > Hi again,
> >
> > I have played with pthread's mutex with this small code:
> >
> >   pthread_mutex_t a,b;
> >
> >   printf("Initialize mutexes...\n");
> >   pthread_mutex_init(&a, NULL);
> >   pthread_mutex_init(&b, NULL);
> >
> >   printf("Trying to lock mutex a..\n");
> >   pthread_mutex_lock(&a);
> >   printf("Got mutex a..\n");
> >
> >   printf("Trying to lock mutex a..\n");
> >   pthread_mutex_lock(&a);       <----------should block here
> >   printf("Got mutex a..\n");
> >
> >   fprintf(stderr,"Done.\n");
> >
> > On Linux, the program will block forever at the second attempt to lock
> > mutex a but on RTEMS it doesn't block. Instead it returns with value 45.
> > Is there any chance to have it blocked here in RTEMS?
>
> That's EDEADLOCK which probably means you are attempting to acquire
> a mutex you already own.
	  ^^^ the context of "you" here = same POSIX thread? I'm playing
with multi-thread program, each thread is competing to get a mutex.

Pattara

>
> Also ... What target and BSP are you using?  If accidentally
> using unix/posix that is an impact since RTEMS POSIX API
> can't be used there.
>
> > Regards,
> > Pattara
> >
> > --
> > Please avoid sending me Word or PowerPoint attachments.
> > See http://www.fsf.org/philosophy/no-word-attachments.html
> > ----------------------------------------------------------------------
> > Ott Pattara Kiatisevi                              T L W G
> > M.Sc. INFOTECH Student, Stuttgart, Germany      http://linux.thai.net/
> > ----------------------------------------------------------------------
>
> --
> Joel Sherrill, Ph.D.             Director of Research & Development
> joel at OARcorp.com                 On-Line Applications Research
> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
>    Support Available             (256) 722-9985
>
>