SDL_assert(3)

💖 SDL_assert 💖

okay bestie so this is SDL_assert(3), part of the SDL3 FUNCTIONS lineup, and she's an absolute icon. let's get into it 🎀

✨ NAME ✨

SDL_assert — an assertion test that is normally performed only in debug builds. yes, she's a debug-build girlie, she does not show up to the end-user party 🦋

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🌸 SYNOPSIS 🌸

#include <SDL3/SDL_assert.h>

#define SDL_assert(condition) if (assertion_enabled && (condition)) { trigger_assertion; }

like. look at her. one macro. so much power. 💅

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👑 DESCRIPTION 👑

okay so here's the tea ☕: this macro is enabled when SDL_ASSERT_LEVEL is >= 2, and disabled otherwise. the whole point is that these tests only run in debug builds, which means a) they can be lowkey expensive (fr fr, they're not free), and b) when one of them fails, she brings everything to a halt so the programmer can be right there to assess the problem. dramatic? yes. correct? also yes 😌

in short: you can sprinkle these around liberally and just assume they will evaporate out of the build when you're building for end-users. gone. poof. not in the binary. ✨

and here's the sneaky-genius part bestie — when assertions are disabled, this wraps condition in a sizeof operator, which means any function calls and side effects will not run, but the compiler will not complain about any otherwise-unused variables that are only referenced in the assertion. no warning spam, no accidental side effects. she thought of everything 🧚

one can set the environment variable "SDL_ASSERT" to one of several strings — "abort", "break", "retry", "ignore", "always_ignore" — to force a default behavior, which may be desirable for automation purposes. like, if you're scripting this whole thing and you don't want a human clicking buttons in a dialog at 3am, that's your move 💀

and ooh, specific scenario, pay attention: if your platform requires GUI interfaces to happen on the main thread but you're debugging an assertion in a background thread, it might be desirable to set this to "break" so that your debugger takes control as soon as assert is triggered, instead of risking a bad UI interaction (deadlock, etc) in the application. no cap, that deadlock is not the vibe 🙈

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🎀 MACRO PARAMETERS 🎀

• condition — boolean value to test. that's it. that's the whole parameter. slay 💅

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🌈 THREAD SAFETY 🌈

it is safe to call this macro from any thread. periodt. go off wherever you want 🫶

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⭐ AVAILABILITY ⭐

this macro is available since SDL 3.2.0. so if you're on something older, bestie, update 😭

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and that's the whole page! brought to you by Simple Directmedia Layer, running on SDL 3.4.18, and stamped with the SDL_assert(3) glow-up 💖 mwah, go write some assertions, i'm obsessed with you 🎀✨