SEM(4)

💖 SEM(4) — bestie we're talking POSIX semaphores 💖

okay so hi, this is the manual page for sem from the Kernel Interfaces Manual, and it's literally all about POSIX semaphores 🎀. it's giving "short but iconic", so let's get into it.

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✨ NAME ✨

sem — POSIX semaphores 🦋

like. that's it. that's the name. short, sweet, slays.

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✨ SYNOPSIS ✨

so there's like three ways to get this driver into your life, and bestie you get to pick your fighter 💅

option one: bake it straight into the kernel 🍓 — drop this line into your kernel configuration file:

options P1003_1B_SEMAPHORES

option two: load it as a module at boot time 🌸 — put this line in loader.conf(5):

sem_load="YES"

option three: load it as a module at run-time ✨ — run this command as root:

kldload sem

three paths, one destiny, no cap. 🔥

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✨ DESCRIPTION ✨

okay so the sem facility is the thing that hands over the system calls that the standard C library (libc) uses to implement POSIX semaphores. it's giving behind-the-scenes main character energy 👑

it offers support for functions like sem_init() and sem_wait() — yk, the semaphore besties 🫶

and it's available in two whole flavours: as a kernel option for static inclusion (baked in, permanent, committed 💍) and as a dynamic kernel module (shows up when you call, leaves when you're done 🙈). both are valid, both are iconic, periodt.

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✨ SEE ALSO ✨

go read these next, they're all part of the semaphore cinematic universe 🌈

• sem_destroy(3)
• sem_getvalue(3)
• sem_init(3)
• sem_open(3)
• sem_post(3)
• sem_wait(3)
• config(8)
• kldload(8)
• kldunload(8)

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✨ HISTORY ✨

the sem facility appeared in FreeBSD 5.0. a legend was born, and honestly? we're still obsessed. 💜

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and that's the whole page, bestie!! 🎀 this one came out of the Debian edition of the man pages, dated February 7, 2014, and it's filed under SEM(4) in the Kernel Interfaces Manual. mwah, go forth and semaphore responsibly. 💅✨🦋