SDL_OUT_BYTECAP(3)

💖 SDL_OUT_BYTECAP 💖

ok so bestie, we're looking at SDL_OUT_BYTECAP(3) — it's one of the SDL3 functions (well, technically a macro, we'll get there) and honestly? it's giving compiler-whisperer energy. no cap.

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✨ NAME ✨

SDL_OUT_BYTECAP — a macro that annotates function params with output buffer size. that's the whole vibe. it's a little sticky note you slap on your function arguments so the compiler knows what's up 🎀

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🌸 SYNOPSIS 🌸

#include <SDL3/SDL_stdinc.h>

#define SDL_OUT_BYTECAP(x) _Out_bytecap_(x)

like, that's it. that's the macro. she's small but she's mighty 💅

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🦋 DESCRIPTION 🦋

okay so picture this: you wanna annotate memcpy. iconic function, everyone knows her. here's how you'd do it:

void *memcpy(SDL_OUT_BYTECAP(bufsize) void *dst, const void *src, size_t bufsize);

so what this is saying is: dst should have a capacity of bufsize bytes in size, and the function only writes to it — it's an output, not an input, periodt. and then the compiler, or whatever other analysis tools you've got in your corner, can literally warn you when that doesn't appear to be the case. like a bestie who notices when something's off 👀

and here's the slay part: on compilers that don't have this annotation mechanism at all? this macro is defined to nothing. literally nothing. she just vanishes. no drama, no errors, just vibes 🌈

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👑 AVAILABILITY 👑

this macro is available since SDL 3.2.0. so if you're on something older, sorry babe, she's not there yet 😭

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🫶 SEE ALSO 🫶

(no see-also entries in the original — she stands alone, main character energy fr fr)

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💀 heads up bestie: on compilers without the annotation mechanism, SDL_OUT_BYTECAP expands to nothing at all, so don't go relying on it to actually do anything at runtime. it's purely a hint for compilers and analysis tools. iykyk ✨

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mwah 💋 that's the whole page. this one came from Simple Directmedia Layer, and the version floating around is SDL 3.4.18 — so go forth, annotate your buffers, and let the compiler be your emotional support bestie 🧚💜