VMS Help RTL Routines, PPL$, PPL$READ_SEMAPHORE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The Read Semaphore Values routine returns the current or maximum
    values, or both, of the specified counting semaphore. The
    semaphore must have been created by PPL$CREATE_SEMAPHORE.

    Format

      PPL$READ_SEMAPHORE  semaphore-id [,semaphore-value]

                          [,semaphore-maximum]

1 - Arguments

 semaphore-id

    OpenVMS usage identifier
    type          longword (unsigned)
    access        read only
    mechanism     by reference
    Identifier of the specified semaphore. The semaphore-id argument
    is the address of an unsigned longword containing the identifier.

    Semaphore-id is returned by PPL$CREATE_SEMAPHORE.

 semaphore-value

    OpenVMS usage word_signed
    type          word (signed)
    access        write only
    mechanism     by reference
    Receives information about the specified semaphore. The optional
    semaphore-value argument is the address of a signed word
    containing the current value of the semaphore or the number of
    blocked processes. If positive, semaphore-value contains the
    number of available resources associated with this semaphore;
    if negative, it contains the number of waiting processes. If the
    value returned is zero, there are no available resources and no
    waiting processes.

 semaphore-maximum

    OpenVMS usage word_signed
    type          word (signed)
    access        write only
    mechanism     by reference
    Maximum value of the semaphore. The semaphore-maximum argument is
    the address of a signed word containing the maximum value of the
    semaphore specified by semaphore-id.