pthread_t in 5.3

Daniel Eischen deischen at
Thu Jan 27 16:47:08 PST 2005

On Thu, 27 Jan 2005, Medi Montaseri wrote:

> Daniel Eischen wrote:
> >Sorry, what pthread_t is, is not for you to know.  It is up to the
> >implementation to define it anyway that it wants.  And is also why
> >there is a pthread_equal() function.
> >
> >>I'm not interested in the pointer, I'm interested in the numerical
> >>thread ID...
> >
> >There is no such thing as defined by POSIX.
> >
> >>Now at this point, you'll think all you have to do is to de-reference
> >>the pointer.
> >>But since 'struct pthrad' is opaque, gdb and myself are clueless to
> >>proceed from here.
> >>Can someone shed some light on this please...
> >>
> >>
> >
> >I think you are trying to do something that is non-standard/portable.
> But on linux, a thread_t is
> typedef unsigned long int pthread_t;
> I guess the idea was if a file descriptor is a int and a socket is an
> int and a process id is an int
> then a thread also be an int and people can have an array of those IDs.

It doesn't matter what Linux does; it matters what the POSIX
standard says.  Nothing precludes pthread_t from being an
int or long, but you shouldn't rely on it being that way.
Even though our pthread_t is an opaque id (pointer), nothing
is stopping you from storing them in an array.  An array of:

	pthread_t tids[NUM_THREADS];

works regardless of the whether you are on Linux or FreeBSD.


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