SVIPC(7)

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:

1、message queues,

2、semaphore, and

3、shared memory.

NOTE:

一、通过下面的描述可知，POSIX对这三种IPC都进行了标准化

二、下面对它们的API进行了对比

Message queues	Semaphore sets	Shared memory segments
msgget(2)	semget(2)	shmget(2)
msgctl(2)	semctl(2)	shmctl(2)

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).

NOTE:

mq_overview(7) 是 "overview of POSIX message queues"

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).

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).

IPC namespaces

For a discussion of the interaction of System V IPC objects and IPC namespaces, see .