Re: pthreads, cygwin and pthread_mutex_lock not blocking

[Peter Rehley <peter at rehley dot net>]

Well, here is a simple test case, but turns out I wasn't using the 
latest version.  I was having the problem on 1.5.12,  I haven't been 
able to get a good build with cygwin 1.5.17-1.  It builds and I can run 
the install script, but when I put the dll in place I see the message 
"cygheap magic number mismatch detected", and gcc doesn't want to work.

I followed the instructions on the FAQ page for building cygwin.  Also 
the only line that I changed was in winsup/cygwin/include/pthread.h, 
line 56

from
#define PTHREAD_MUTEX_DEFAULT PTHREAD_MUTEX_ERRORCHECK
to
#define PTHREAD_MUTEX_DEFAULT PTHREAD_MUTEX_NORMAL

On the unmodified cygwin 1.5.17, the parent lock returns 45 (EDEADLK)

On May 28, 2005, at 9:15 AM, Christopher Faylor wrote:

> On Fri, May 27, 2005 at 04:35:39PM -0700, Peter Rehley wrote:
> > On May 27, 2005, at 1:28 PM, Christopher Faylor wrote:
> >
> > > On Fri, May 27, 2005 at 10:57:34AM -0700, Peter Rehley wrote:
> > > > I'm trying to use pthread in cygwin, and I'm expecting the function
> > > > pthread_mutex_lock to block when used.  However it is returning 
> > > > error
> > > > 45 (EDEADLK).    I'm using a static initializer for the thread so 
> > > > the
> > > > mutex is type PTHREAD_MUTEX_DEFAULT.
> > > > When I look through the pthread code I see that 
> > > > PTHREAD_MUTEX_DEFAULT
> > > > is set to PTHREAD_MUTEX_ERRORCHECK,
> > > > When I do the same on linux or soloris, the pthread_mutex_lock 
> > > > blocks,
> > > > and looking in the pthread.h file on those systems see that  the
> > > > default is set to PTHREAD_MUTEX_NORMAL.
> > > >
> > > > Why is cygwin using PTHREAD_MUTEX_ERRORCHECK as the default?  And 
> > > > what
> > > > problems might occur if PTHREAD_MUTEX_DEFAULT is set to
> > > > PTHREAD_MUTEX_NORMAL?
> > >
> > > Why not just try it and report the results?
> > Done.  Hangs at WaitForSingleObject.
>
> Can you provide a STC(tm) (simple test case) which demonstrates the
> problem both with and without PTHREAD_MUTEX_ERRORCHECK?
>
> cgf
>
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Enjoy,
Peter
-------------------------------
A Møøse once bit my sister

Attachment: fork_test.c
Description: Text document

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