mouse_callback(3)

💖 mouse_callback(3) 💖

okay bestie, so this is a page from the Allegro manual (the game programming library, yes THAT Allegro) and it's about mouse_callback — a lil function pointer you get to fill in yourself. group chat, gather round 🫶

✨ NAME ✨

mouse_callback — the mouse callback that you specify. it's part of the Allegro game programming library, and it is exactly as niche and exactly as powerful as it sounds 💅

🌸 SYNOPSIS 🌸

#include <allegro.h>

extern void (*mouse_callback)(int flags);

that's it. that's the whole thing. a function pointer just vibing out there in the open, waiting for you to point it at something 😌

🦋 DESCRIPTION 🦋

so here's the tea, bestie: the interrupt handler calls this thing whenever the mouse moves or whenever one of the buttons changes state. that's the whole job description.

🚨 TWO HARD RULES, no cap: this function must live in locked memory, and it must execute _very_ quickly! like, blink-and-you-missed-it fast. it's running from an interrupt handler, so do not be out here doing side quests in there 😭

it gets passed the event flags that triggered the call — and those flags are a bitmask containing any of these values:

• MOUSE_FLAG_MOVE 🌈
• MOUSE_FLAG_LEFT_DOWN 🖱️
• MOUSE_FLAG_LEFT_UP 🖱️
• MOUSE_FLAG_RIGHT_DOWN 🖱️
• MOUSE_FLAG_RIGHT_UP 🖱️
• MOUSE_FLAG_MIDDLE_DOWN 🖱️
• MOUSE_FLAG_MIDDLE_UP 🖱️
• MOUSE_FLAG_MOVE_Z 🌀

⚠️ important caveat, don't skip this one: even if your mouse has more than three buttons, only the first three can be trapped using a callback. the rest of your extra buttons are just… not invited to this party 🙈

🎀 SEE ALSO 🎀

• install_mouse(3) — go read that one next, bestie, it's the prequel 💜

and that's the whole page, you ate it, periodt 👑

this lil love letter was brought to you by Allegro, version 4.4.3 — mwah, catch you in the next manpage 💖🎀🦋