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|SVIPC(7)||Linux Programmer's Manual||SVIPC(7)|
sysvipc - System V interprocess communication mechanisms
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.
System V message queues allow data to be exchanged in units called messages. Each messages 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:
- 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.
- Add a message to a queue.
- Remove a message from a queue.
- Perform various control operations on a queue, including deletion.
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:
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:
- Create a new segment or obtain the ID of an existing segment. This call returns an identifier that is used in the remaining APIs.
- Attach an existing shared memory object into the calling process's address space.
- Detach a segment from the calling process's address space.
- Perform various control operations on a segment, including deletion.
For a discussion of the interaction of System V IPC objects and IPC namespaces, see ipc_namespaces(7).
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)
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