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.
Add a message to a queue.
Remove a message from a queue.
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.
Perform operations on the semaphores in a set.
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.
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.
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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