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NAME bus - A simple daemonless system for broadcasting messages locally

DESCRIPTION bus is a simple daemonless system for broadcasting messages locally. It is a lightweight alternative to a two-phase interprocess flexible barrier.

bus uses a System V semaphore array and System V shared memory.
Buses are named; the key of the semaphore array and the shared
memory is stored in a regular file.

The shared memory used by bus is always 2048 bytes. Additionally
all messages should be encoded in UTF-8 and not contain any NULL
characters, except they MUST always end with a zero byte.
Furthermore messages should be prefixed with the process
identifer of the process whence the message originated, followed
by a space. If the process is ephemeral, 0 should be used instead
of the process identifier.

Communication over bus is synchronous. The broadcast call does
not return until all listeners have received (and copied) the
message. A malfunctioning program can lock the bus.

This software package contains a C library and a command line
utility. The package python-bus provides a Python 3 module.

RATIONALE We need an interprocess communication system similar to message queues. But we need broadcasting rather than anycasting, so we have a fast, simple and daemonless system for announcing events to any processes that might be interested.

SEE ALSO libshr(7), cmdipc(1), msgctl(3), semctl(3), shmctl(3), mqueue.h(0), semaphore.h(0), sem_overview(7), mmap(3), pipe(3), socketpair(3), socket(3), unix(7), cmsg(3), kill(3), eventfd(2), memfd_create(2), pthread_mutex_destroy(3), pthread_rwlock_destroy(3), futex(7), pthread_spin_destroy(3), pthread_cond_destroy(3), lockf(3), flock(2), fcntl(3), ioctl(3), mkfifo(3), rendezvous(2), 9p(2), libdoor(3), python-bus