SDL_Semaphore(3type)

💖 SDL_Semaphore 💖

okay bestie, welcome to the SDL_Semaphore page — it lives in the SDL3 DATATYPES corner of the manual and it's genuinely one of the most useful little gremlins in the whole threading toolbox, no cap 🫶

---

✨ NAME ✨

SDL_Semaphore — a means to manage access to a resource, by count, between threads.

yes bestie that's the whole vibe: it's a bouncer for your resource, and the bouncer counts heads 💅

---

🌸 SYNOPSIS 🌸

#include <SDL3/SDL_mutex.h>

typedef struct SDL_Semaphore SDL_Semaphore;

like, that's it. one header, one opaque struct. she's lowkey mysterious, and that's the point 🔥

---

🦋 DESCRIPTION 🦋

okay so. Semaphores — specifically the "counting semaphores" flavor — let X number of threads request access at the same time. every time a thread gets granted access, the counter goes down by one. iconic. 💖

and then? when the counter hits zero, any future requests just block. they sit there. they wait. not a vibe, but a necessary one. 😭 they stay parked until a prior thread releases their request, which bumps the counter back up again. then the door opens and somebody else gets in. the way that works is honestly so clean. ✨

Wikipedia has a thorough explanation of the concept:

https://en.wikipedia.org/wiki/Semaphore_(programming)

fr fr, go read it if you want the full lore. i'm just the group chat summary, she's the whole textbook. 📚

---

👑 AVAILABILITY 👑

This struct is available since SDL 3.2.0. so if you're on anything older, sorry bestie, she's not there yet. 🙈

---

🌈 SEE ALSO 🌈

not gonna lie, this page doesn't list any SEE ALSO friends. it's giving solo main character energy. 💀 but the header lives in <SDL3/SDL_mutex.h> so that's your neighborhood. 🎀

---

okay that's the whole page, bestie!! stay safe out there, don't forget to release your requests or your threads will be waiting forever and that's not the slay we're going for 💅

signing off with love from the Simple Directmedia Layer girlies, this is SDL 3.4.18 energy, mwah 💋✨🦋🌸