File:           pthread.tgz
Description:    POSIX kernel-level threads for QNX4
Keywords:       POSIX, threads, kernel, library, mutex, condition variable
Version:       	1.00 beta
Entered-date:   Aug 27, 1998
Author:         Steve Furr
Ported-by:	
Original-site:	qnx
Copying-policy: copyright
Supplemental:   

Thread library for QNX4 compatible with the POSIX 1003.1c standard.
The library implements kernel level threads as opposed to user-level
threads for better integration with QNX message passing and blocking
I/O calls.  The library provides all synchronization primitives 
required by the standard including synchronization variables and
thread synchronization.  The library replaces a number of
standard library calls with thread-safe versions (e.g. sleep()) or to
introduce thread cancellation points as mandated by the specification.
All I/O calls are also replaced to insure that file descriptors
are correctly shared between threads (i.e. shared following tfork(),
not just inherited).


REQUIREMENTS
------------

 o  Watcom C 11.0 beta (10.6 *may* work)
 o  QNX 4.25C revision of Proc
 o  Fsys.424(?)  - Fsys version that supports arbitray _IO_DUP messages
                   from the appropriate effective user id.

COMPILATION
-----------

Programs using the POSIX threads library must be compiled with
stack based calling conventions.

Programs must be linked with -lpthreads and -lsys.


CAVEATS
-------

There is one known limitation on the use of the library.  It isn't
safe to call getpid() within a multi-threaded program and store
the pid for later use, unless a thread has already been created,
or the pthread_self() function has been called.  This is because
the primordial thread is morphed into a different process when the
library initializes itself and creates a synchronization thread.