POSIX Semaphores API

name: POSIX Semaphores API
description: POSIX named and unnamed semaphore interfaces for process and thread synchronization.
image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg
humanURL: https://man7.org/linux/man-pages/man7/sem_overview.7.html
baseURL: system://unix/semaphores
tags:
- Concurrency
- Ipc
- Semaphores
- Synchronization
properties:
- type: Documentation
  url: https://man7.org/linux/man-pages/man7/sem_overview.7.html
- type: Documentation
  url: https://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_open.html
operations:
- name: sem_open
  description: Open or create a named semaphore
  parameters:
  - name
  - oflag
  - mode
  - value
  returns: pointer to semaphore, SEM_FAILED on error
- name: sem_close
  description: Close a named semaphore
  parameters:
  - sem
  returns: 0 on success, -1 on error
- name: sem_unlink
  description: Remove a named semaphore
  parameters:
  - name
  returns: 0 on success, -1 on error
- name: sem_init
  description: Initialize an unnamed semaphore
  parameters:
  - sem
  - pshared
  - value
  returns: 0 on success, -1 on error
- name: sem_destroy
  description: Destroy an unnamed semaphore
  parameters:
  - sem
  returns: 0 on success, -1 on error
- name: sem_wait
  description: Lock (decrement) a semaphore, blocking if value is zero
  parameters:
  - sem
  returns: 0 on success, -1 on error
- name: sem_trywait
  description: Try to lock a semaphore without blocking
  parameters:
  - sem
  returns: 0 on success, -1 on error
- name: sem_timedwait
  description: Lock a semaphore with a timeout
  parameters:
  - sem
  - abs_timeout
  returns: 0 on success, -1 on error
- name: sem_post
  description: Unlock (increment) a semaphore
  parameters:
  - sem
  returns: 0 on success, -1 on error
- name: sem_getvalue
  description: Get the current value of a semaphore
  parameters:
  - sem
  - sval
  returns: 0 on success, -1 on error