Sorry, I missed your emphasis.
No, it isn't possible to just change one of the threads. The pthreads in *nix systems are light-weight compared to the Windows equivalent, and share more state information. The POSIX standard requires that they share user and group ids.
Incidentally, a fork is much faster than a CreateProcess on Windows (CreateProcess is something more akin to vfork+exec). For a long time fork was the only way to do multitasking in Unix, so it is well optimized for the job. Not sure if that makes it any more palatable?
Last edited by neonsignal; 07-31-2009 at 03:38 AM.