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     RENDEZVOUS(2)                                       RENDEZVOUS(2)

          rendezvous - user level process synchronization

          ulong rendezvous(ulong tag, ulong value)

          The rendezvous system call allows two processes to synchro-
          nize and exchange a value.  In conjunction with the shared
          memory system calls (see segattach(2) and fork(2)), it
          enables parallel programs to access the system scheduler.

          Two processes wishing to synchronize call rendezvous with a
          common tag, typically an address in memory they share.  One
          process will arrive at the rendezvous first; it suspends
          execution until a second arrives.  When a second process
          meets the rendezvous the value arguments are exchanged
          between the processes and returned as the result of the
          respective rendezvous system calls.  Both processes are
          awakened when the rendezvous succeeds.

          The tag space is common to processes in the same file name

          If a rendezvous is interrupted the return value is ~0, so
          that value should not be used in normal communication.

          segattach(2), fork(2)

          Sets errstr.