sysvipc(7) — Linux manual page

sysvipc(7)          Miscellaneous Information Manual          sysvipc(7)

NAME

       sysvipc - System V interprocess communication mechanisms

DESCRIPTION

       System V IPC is the name given to three interprocess
       communication mechanisms that are widely available on UNIX
       systems: message queues, semaphore, and shared memory.

   Message queues
       System V message queues allow data to be exchanged in units
       called messages.  Each message can have an associated priority.
       POSIX message queues provide an alternative API for achieving the
       same result; see mq_overview(7).

       The System V message queue API consists of the following system
       calls:

       msgget(2)
              Create a new message queue or obtain the ID of an existing
              message queue.  This call returns an identifier that is
              used in the remaining APIs.

       msgsnd(2)
              Add a message to a queue.

       msgrcv(2)
              Remove a message from a queue.

       msgctl(2)
              Perform various control operations on a queue, including
              deletion.

   Semaphore sets
       System V semaphores allow processes to synchronize their actions.
       System V semaphores are allocated in groups called sets; each
       semaphore in a set is a counting semaphore.  POSIX semaphores
       provide an alternative API for achieving the same result; see
       sem_overview(7).

       The System V semaphore API consists of the following system
       calls:

       semget(2)
              Create a new set or obtain the ID of an existing set.
              This call returns an identifier that is used in the
              remaining APIs.

       semop(2)
              Perform operations on the semaphores in a set.

       semctl(2)
              Perform various control operations on a set, including
              deletion.

   Shared memory segments
       System V shared memory allows processes to share a region a
       memory (a "segment").  POSIX shared memory is an alternative API
       for achieving the same result; see shm_overview(7).

       The System V shared memory API consists of the following system
       calls:

       shmget(2)
              Create a new segment or obtain the ID of an existing
              segment.  This call returns an identifier that is used in
              the remaining APIs.

       shmat(2)
              Attach an existing shared memory object into the calling
              process's address space.

       shmdt(2)
              Detach a segment from the calling process's address space.

       shmctl(2)
              Perform various control operations on a segment, including
              deletion.

   IPC namespaces
       For a discussion of the interaction of System V IPC objects and
       IPC namespaces, see ipc_namespaces(7).

SEE ALSO

       ipcmk(1), ipcrm(1), ipcs(1), lsipc(1), ipc(2), msgctl(2),
       msgget(2), msgrcv(2), msgsnd(2), semctl(2), semget(2), semop(2),
       shmat(2), shmctl(2), shmdt(2), shmget(2), ftok(3),
       ipc_namespaces(7)

COLOPHON

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Linux man-pages 6.9.1          2024-05-02                     sysvipc(7)

Pages that refer to this page: ipcmk(1), ipcrm(1), ipcs(1), lsipc(1), intro(2), ipc(2), msgctl(2), msgget(2), msgop(2), semctl(2), semget(2), semop(2), shmctl(2), shmget(2), shmop(2), ftok(3), proc_sysvipc(5), systemd.exec(5), ipc_namespaces(7)

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