0                  Successful completion.
    -1                 Indicates an error. The function sets errno to
                       one of the following values:

                       o  EINVAL - The value argument exceeds {SEM_
                          VALUE_MAX}.

                       o  ENOSYS - The function is not implemented.

                       o  EVMSERR - OpenVMS specific nontranslatable
                          error code.