OpenBSD: crashing

Stuart Henderson stu at
Fri May 10 07:24:56 UTC 2013

On 2013/05/09 13:30, noselasd at wrote:
> On 04/20/2013 05:59 AM, Alan Corey wrote:
> > > I've just got hold of a card and looking into this.
> >
> >Do you mean a dongle?  I got one of the $20 ones, which works pretty
> >well in Windows with SDR# and RTL1090, so I bought a second one.
> >
> > >
> > > By specification, pthread_mutex_unlock() has undefined behaviour when
> > > unlocking a mutex which is already unlocked.
> Note also that rtl_fm uses mutexes as semaphores/condition variables,
> it locks mutexes in one thread and unlocks them in another thread -
> which is undefined behavior (Except if the mutex is recursive or error
> checking, in which case pthread_mutex_unlock must
> detect this situation and return an error).
> You're only supposed to unlock a mutex by the same thread that locked
> it, and it's possible OpenBSD bails out if you do otherwise.

Is there a reason for doing it this way rather than using sem_post
and sem_wait?

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