Re: pthread_create -- no callback?

["Gareth Pearce" <tilps at hotmail dot com>]

----- Original Message -----
From: "Lassi A. Tuura" <lassi.tuura@cern.ch>
To: "Evan Pollan" <evan_pollan@yahoo.com>
Cc: <cygwin@cygwin.com>
Sent: Thursday, November 15, 2001 2:28 AM
Subject: Re: pthread_create -- no callback?


> > The sample I included did check the return value of pthread_join.
>
> Nope, you are still not printing pthread_join *return* value -- print
> the int returned by pthread_join as you did with pthread_create.  On
> linux it returns ESRCH = no such thread.  Your problem is with the
> thread argument to pthread_join as shown below.
>
> Since you are not joining with the thread, the output might disappear.
> My guess is that the main thread finishes execution and the stdout gets
> closed before the second thread executes, and hence you see no output
> from the other thread.  That doesn't happen on linux as you can see
> below, but maybe it is reasonable behaviour on windows.  If you think it
> is a bug, I am sure cygwin authors would appreciate a patch ;-)
no such thread implies that the thread has already completed execution,
doesnt it?, so therefore the problem would have to be something along the
lines of threads not having their buffers flushed before exiting? - just a
guess
however under cygwin ... if you replace the print statement with a variable
incriment - it doesnt take place either... wish I knew why ... debugging mt
apps is not my idea of fun though ... so I am not about to discover whats
wrong so I can patch it...

*vague though that the thread might not be fully created when pthread_create
returns or something...*

hmm i should sleep instead of posting - probably will look silly in the
morning...
>
> Your code:
> >     void* threadExitStatus;
> >     cout << "--> pthread_join()\n";
> >     pthread_join(&thread, &threadExitStatus);
> >     cout << "<-- pthread_join():" << (int)threadExitStatus << "\n";
>
> Change this to:
>       retVal = pthread_join(&thread, &threadExitStatus);
>       cout << "<-- pthread_join():" << retVal
>            << " " << (int)threadExitStatus << "\n";
>
> I would have expected you to see this in your compilation:
> /tmp/foo.cxx:24: warning: passing `pthread_t *' to argument 1 of
>     `pthread_join(long unsigned int, void **)' lacks a cast
>
> Output with my changes (on linux):
> $ ./a.out
> --> pthread_create()
> <-- pthread_create():0
> --> pthread_join()
> <-- pthread_join():3 1075347592
> --> callbackFunction(0x8048b9b)
> $ grep ESRCH /usr/include/asm/errno.h
> #define ESRCH            3      /* No such process */
>
> HTH,
> //lat
> --
> Those who cannot remember the past are condemned to repeat it.
> --George Santayana
>
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