SDL_SetAssertionHandler(3)

💅 SDL_SetAssertionHandler — bestie edition

okay so this is a page from the SDL3 FUNCTIONS manual, and the function we're hyping up today is SDL_SetAssertionHandler. she's giving "let me handle my own drama" energy and honestly? iconic. 💖

---

✨ NAME ✨

SDL_SetAssertionHandler — set an application-defined assertion handler. 🎀

---

🌸 SYNOPSIS 🌸

#include <SDL3/SDL_assert.h>

void SDL_SetAssertionHandler(
                SDL_AssertionHandler handler,
                void *userdata);

---

🦋 DESCRIPTION 🦋

so the way this works is: this function lets your app show its own assertion UI, and/or force what the response to an assertion failure is gonna be. like, you get to be the main character of your own crash handling. 💅

but if you don't provide one? no worries, SDL will try to do the right thing on its own — popping up a system-specific GUI dialog, and probably minimizing any fullscreen windows. she's got you either way. ✨

now here's the part where you gotta pay attention, bestie:

• this callback may fire from any thread, but it runs wrapped in a mutex, so it will only fire from one thread at a time. so no chaotic multi-thread pileup, the mutex is holding the door. 🚪

⚠️ and listen — this callback is NOT reset to SDL's internal handler upon SDL_Quit()! not me warning you about this. it stays. periodt. 💀

---

🎀 FUNCTION PARAMETERS 🎀

• handler — the SDL_AssertionHandler function to call when an assertion fails, or NULL for the default handler. (yes, NULL is a valid vibe here, it just means "SDL, you take it." 🫶)
• userdata — a pointer that is passed to handler. little gift you hand over, she'll carry it for you. 🎁

---

🔥 THREAD SAFETY 🔥

it is safe to call this function from any thread. go off, gorl. 🌈

---

⭐ AVAILABILITY ⭐

this function is available since SDL 3.2.0. she's not new-new, but she's not ancient either. iykyk. 👑

---

👀 SEE ALSO 👀

• SDL_GetAssertionHandler(3) — the other half of this situationship, go read her too. 💜

---

Simple Directmedia Layer — SDL 3.4.18 — and that's the whole page, bestie!! tysm for reading, drink some water, and may all your assertions be handled exactly the way you want them. mwah 💋🦋🌸🎀✨