-=> Quoting Mike Burgett to Phil Crown <=-

 PC>   rc = something;
 PC>   str = somethingtoo;  // this also needs protecting because str is
 PC>                        // used in another function that is also
 PC>                        // called by two or more threads.
 PC>   release.MutexSem();
 PC>   return rc;  // A calling thread is pre-empted here before returning
 PC> rc.
 PC>               // A second threads comes along and completes the
 PC>               // function before the first thread has finished,
 PC>               // thus causing rc to contain invalid data.
 PC>               // Is this possible?
 PC> }

 MB> No, because they're using different copies of rc.  It is possible
 MB> though, that str is changed, since the declaration of str isn't shown
 MB> here, I assume it's not an auto variable. 

str is part of a class.

The mutex semaphores must be working because my program has stopped
trapping (fingers crossed). :-)

Phil Crown
pcrown{at}airmail.net
http://web2.airmail.net/pcrown/

--- Blue Wave/OS2 v2.30