SDL_HintCallback(3type)

💖 SDL_HintCallback 💖

okay so bestie, welcome to the SDL3 DATATYPES corner of the manual, and today's main character is SDL_HintCallback — the little function-pointer glow-up that lets you get pinged every time a hint value changes. yes, we're doing callbacks. no, it's not scary. i promise. 🫶

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✨ NAME ✨

SDL_HintCallback — a callback used to send notifications of hint value changes. it's giving "call me when things change" but, like, in C. 📞

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🌸 SYNOPSIS 🌸

#include <SDL3/SDL_hints.h>

typedef void(SDLCALL *SDL_HintCallback)(void *userdata, const char *name, const char *oldValue, const char *newValue);

that's the whole signature, bestie. four params, no return value, SDLCALL right there in the middle like the icon it is. 💅

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🦋 DESCRIPTION 🦋

so here's the tea: this callback gets called an initial time during SDL_AddHintCallback, handing you the hint's current value. after that, it fires again each time the hint's value changes. 🔥

and listen — in that very first call, the current value is sitting in both oldValue and newValue. like, both. same value. twice. that's not a bug, that's just the vibe. don't @ me. 🙈

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🎀 FUNCTION PARAMETERS 🎀

• userdata — literally just whatever you passed as userdata to SDL_AddHintCallback(). it comes right back to you. bestie behavior. 💜
• name — what you passed as name to SDL_AddHintCallback(). the hint's name, hand-delivered.
• oldValue — the previous hint value. the before pic. 📸
• newValue — the new value the hint is to be set to. the after pic. ✨

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🧚 THREAD SAFETY 🧚

lowkey important, so pay attention: this callback is fired from whatever thread is setting a new hint value. 🌈

and SDL holds a lock on the hint subsystem while calling this callback. so yes, there's a lock. respect the lock. 🔒

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⭐ AVAILABILITY ⭐

this datatype has been available since SDL 3.2.0. so if you're on something older… babe, upgrade. 👑

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💀 SEE ALSO 💀

• SDL_AddHintCallback(3)

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okay that's the whole page, bestie, you ate that 🍓 go forth and register your callbacks. this iconic little writeup came to you courtesy of Simple Directmedia Layer for SDL 3.4.18 — mwah, talk later 💖✨🎀