sem

    The location to receive the descriptor of the initialized
    semaphore.

 pshared

    A value indicating whether the semaphore should be sharable
    between the creating process and its descendants (nonzero value)
    or not (zero).

                                   NOTE

       The value for pshared must be zero between threads because
       this release does not support unnamed semaphores to be
       shared across processes.

 value

    The initial value to be given to the semaphore.