SDL_SETAUDIOSTREAMGETCALLBACK(3)

💖 SDL_SetAudioStreamGetCallback 💖

okay bestie, so this is a lil function from SDL3's audio toolkit — the manual page is literally called SDL_SetAudioStreamGetCallback(3) and it lives under the SDL3 FUNCTIONS umbrella. it's giving "let me hook you up with a callback for when somebody wants audio from your stream" energy and honestly? iconic. 🎀

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✨ NAME ✨

SDL_SetAudioStreamGetCallback — set a callback that runs when data is requested from an audio stream. yes queen, you're literally assigning a lil helper that fires the second someone comes asking for audio. 🫶

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🌸 SYNOPSIS 🌸

#include <SDL3/SDL_audio.h>

bool SDL_SetAudioStreamGetCallback(SDL_AudioStream *stream, SDL_AudioStreamCallback callback, void *userdata);

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🦋 DESCRIPTION 🦋

so here's the tea: this callback gets called before data is obtained from the stream. that's the whole point — it hands your callback the chance to add more data on-demand. no cap, it's a pre-game moment. 💅

inside that callback you can (totally optional, no pressure) call SDL_PutAudioStreamData() to add more audio to the stream while it's happening. and if it's needed, the very request that triggered this callback will scoop up that new data immediately. slay.

the callback's additional_amount argument is roughly how many bytes of unconverted data (in the stream's input format) the caller needs — although ngl, this may overestimate a little, just for safety. it factors in how much is already sitting in the stream and only asks for the extra bits necessary to resolve the request. which means (and this is important, bestie) the callback may be asked for zero bytes, and a different amount on each call. it's unpredictable like that. 🙈

your callback is not required to supply exact amounts. it's allowed to supply too much, too little, or literally none at all. the caller will get what's available, up to the amount they requested, regardless of how this callback turned out. so breathe. you can't mess this up that bad. ✨

clearing or flushing an audio stream does not call this callback. periodt.

this function obtains the stream's lock, which means any existing callback (get or put) that's currently in progress will finish running before the new callback gets set. so it's a polite little queue situation, no stepping on toes. 💜

setting a NULL function turns off the callback. bye bestie 👋

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🎀 FUNCTION PARAMETERS 🎀

• stream — the audio stream to set the new callback on. this is the one getting the glow-up.
• callback — the new callback function to call when data is requested from the stream. the main character of this whole situation, fr fr.
• userdata — an opaque pointer provided to the callback for its own personal use. it's giving "here's your little bag of secrets, nobody else peeks". 🤫

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⭐ RETURN VALUE ⭐

returns true on success or false on failure; call SDL_GetError() for more information. and heads up — this only fails if stream is NULL. that's the one and only way to fumble it. 💀

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🌈 THREAD SAFETY 🌈

it is safe to call this function from any thread. yes bestie, any thread, go wild, she's versatile like that. 👑

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🧚 AVAILABILITY 🧚

this function is available since SDL 3.2.0. so if you're on something older... ma'am. 😭

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🔥 SEE ALSO 🔥

• SDL_SetAudioStreamPutCallback(3)

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Simple Directmedia Layer · SDL 3.4.18 · SDL_SetAudioStreamGetCallback(3) — that's the whole page babes, go set some callbacks and stream that audio, mwah 💖✨🎀