Stdlib: sem_get()/sem_acquire()/sem_release() — System V semaphores (ext/sysvsem parity) #3704

Category

stdlib / runtime

Problem

PHP exposes System V semaphore IPC via sem_get(), sem_acquire(), sem_release(), and sem_remove(). Related shared-memory APIs are tracked in #3344 (shmop_*); message queues in #3666 (msg_*). This compiler implements none of the semaphore family (function_exists('sem_get') → false).

php-src reference

• php/php-src ext/sysvsem/sysvsem.c — zif_sem_get, zif_sem_acquire, zif_sem_release, zif_sem_remove
• php/php-src ext/sysvsem/php_sysvsem.h

Repro (today)

<?php
var_dump(function_exists('sem_get'), function_exists('sem_acquire'));
$key = ftok(__FILE__, 'a');
$sem = @sem_get($key, 1);

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php repro.php'
php repro.php   # Zend (requires sysvsem extension enabled)

Scope (this repo)

v1 subset: blocking sem_acquire($sem) only; document nowait / auto-release flags vs Zend.

Done when

• sem_get + sem_acquire + sem_release callable on VM where host supports SysV sem
• Two-process PHPT or documented manual repro: second acquire blocks until release
• ./script/ci-fast.sh --filter sem_acquire green (or @group sysv skip when unavailable)

Related

• Stdlib: shmop_open/read/write/size/close/delete — System V shared memory (ext/sysvshm parity) #3344 — shmop_* shared memory
• Stdlib: ext/sysvmsg — msg_send/msg_receive/msg_get_queue (ext/sysvmsg parity) #3666 — msg_* message queues
• Stdlib: getopt() — CLI short/long option parsing (ext/standard/getopt.c parity) #3251 — ftok() (companion for key generation; file if still missing)