In the Linux world, there are many interprocess communication (IPC) methods available for system programmers. After some web searching, I found that there are rarely blogs or books that summarize them all. This article roughly lists them all with minimal explanation and some links to official manuals.

POSIX IPCs

POSIX-flavor IPCs include semaphores, shared memory, and message queues.

semaphore

There are also two subtypes of semaphores: named and unnamed. For details, see man 7 sem_overview.

sem_getvalue(3)
sem_post(3)
sem_wait(3)
sem_trywait(3)
sem_timedwait(3)
sem_open(3)    // named
sem_close(3)   // named
sem_unlink(3)  // named
sem_init(3)    // unnamed
sem_destroy(3) // unnamed


shared memory

POSIX shared memory (shm) IPC only has named version, the shm objects are stored in Linux tmpfs (by default /dev/shm).

shm_open (3)
shm_unlink (3)


message queue

POSIX message queue (mq) IPC objects are also named, but they are stored in a special filesystem, mqueue. A mqueue filesystem can be mounted with the following command,

mount -t mqueue none /dev/mqueue


The libc APIs and their syscall counterparts are listed below, details see man 7 mq_overview.

Library interface    System call
mq_close(3)          close(2)
mq_getattr(3)        mq_getsetattr(2)
mq_notify(3)         mq_notify(2)
mq_open(3)           mq_open(2)
mq_receive(3)        mq_timedreceive(2)
mq_send(3)           mq_timedsend(2)
mq_setattr(3)        mq_getsetattr(2)
mq_timedreceive(3)   mq_timedreceive(2)
mq_timedsend(3)      mq_timedsend(2)
mq_unlink(3)         mq_unlink(2)


SystemV / XSI IPCs

Similar to the POSIX IPCs, SystemV/XSI-flavor IPCs have the same three types IPCs under Linux: semaphore, shared memory, and message queue. For details, see man 7 sysvipc.

semaphore

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

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.


message queue

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.


UNIX IPCs

There are some IPCs widely implemented in UNIX-like OSs, but not specified in the POSIX standard. These include pipe, FIFO, signal, and unix domain socket.

Pipe & FIFO

The pipe IPC and FIFO are fundamentally the same, except that FIFO is named while pipe is not.

popen(3)      // pipe

pclose(3)     // pipe

mkfifo(3)     // FIFO

mkfifoat(3)   // FIFO


Signal

For details see man 7 signal.

signal(2)

sigaction(2)

kill(2)

sigprocmask(2)

sigpending(2)

sigsuspend(2)

// and more ...


Unix Domain Socket

Unix domain sockets (UDS) use the socket programming interface for local IPC. For details, see man 7 unix.

socket(AF_UNIX, ...) (2)


Modern Linux IPCs

Binder

The binder IPC was initially implemented for the Android OS and has been merged into Linux upstream.
For details, see The Android binderfs Filesystem — The Linux Kernel documentation.

DBus / kdbus

The DBus IPC is now widely used. It is implemented in userspace. Efforts are made towards a kernel version (kdbus), but it has not been merged upstream. For details, see dbus (www.freedesktop.org).