Conference helix::vxworks

277.0. "POSIX threads 1003.1c" by HELIX::MIANO (My parents think I'm in college) Wed Apr 09 1997 12:58

    The implementation of POSIX Threads in VxWorks for Alpha V5.2B is based
    on a draft version of the POSIX threads specification from about 1990.
    The implementation was done by Digital. Wind River has never
    implemented POSIX threads.

    The threads specification has since become a standard -- POSIX 1003.1c.
    With a Wind River V5.3/Tornado merge looming, we are now faced with
    what to do with our implementation of the old draft. There are several
    options, which involve either removing POSIX threads support or
    updating it to be current.

    We could just remove it and pretend it never existed. POSIX threads is
    non-standard VxWorks functionality. Of course, this would affect any
    customer whose application is using the draft implementation. They'd
    have to stay where they are (i.e. VxWorks V5.2B) or port their code to
    use VxWorks tasks instead of POSIX threads.

    We could update threads to the 1003.1c standard. This would also affect
    existing customers. The standard is sufficiently different from the
    draft so that existing applications will be completely broken. I'm not
    sure how big of an issue this really is. Customers assume certain risks
    upon themselves by coding their application to a draft standard. They
    have to expect that the final standard would be implemented someday. 

    We could support both the current draft version and the standard
    version at once for a while. I'm not all that excited about this idea.
    There is enough commonality between the two in routine names and header
    file names to make this a distribution and support nightmare.

    Finally, there's the question of what Wind River will do during the
    DEC/Wind merge. They may not want POSIX threads in their product. Even
    if we update POSIX threads now, it could get kicked out later.

    We're interested in your input. Is your customer using POSIX threads?
    Will they be upset if it's removed? Will they be upset if it's
    radically changed to support the real standard? Will they really be
    happy using the obsolete version of POSIX threads forever?

    Please feel free to add your comments as a reply to this note. If
    you're shy, send mail to HELIX::REALTIME.

    M

    Having received no input from the field, we made a decision without it.
    
    VxWorks V5.2C will contain an update to POSIX threads to the final
    POSIX 1003.1c, which is now a standard. Existing applications which use
    POSIX threads will have to be modified.