SVIPC
Section: Linux Programmer's Manual (7)
Updated: 2020-04-11
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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 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:
- 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
This page is part of release 5.11 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- DESCRIPTION
-
- Message queues
-
- Semaphore sets
-
- Shared memory segments
-
- IPC namespaces
-
- SEE ALSO
-
- COLOPHON
-
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