keyboard_callback(3)

✨ keyboard_callback(3) ✨

okay bestie, welcome to the Allegro manual 💖 this one's from the Allegro game programming library, and it's literally about the lil hook you can plug into the keyboard so you get a say in what keys even mean. 🎀

🌸 NAME 🌸

keyboard_callback — the user-specified keyboard callback handler. it's giving Allegro game programming library. 👑

🦋 SYNOPSIS 🦋

#include <allegro.h>

extern int (*keyboard_callback)(int key);

💅 DESCRIPTION 💅

so here's the tea ☕ if you set this function, the keyboard handler calls it in response to every single keypress. no cap, every one. 💀

it gets handed a copy of the value that's about to get yeeted into the input buffer, and then you get to decide what happens next:

• return that value unchanged → business as usual, bestie
• return zero → the key gets ignored entirely, poof, gone 🙈
• return a modified value → you literally change what readkey() will later return. main character energy fr fr ✨

🚨 okay important, do not skip this: this routine executes in an interrupt context, so it must be in locked memory. that's not a vibe suggestion, that's a requirement. 😭

example time, here's the whole situation:

   int enigma_scrambler(int key)
   {
      /* Add one to both the scancode and ascii values. */
      return (((key >> 8) + 1)
   }
   END_OF_FUNCTION(enigma_scrambler)

   ...

      install_timer();
      LOCK_FUNCTION(enigma_scrambler);
      install_keyboard();
      keyboard_callback = enigma_scrambler;

and one more lil note before you go 🫶 — this callback will be ignored if you also set the unicode keyboard callback. pick a lane, babe. 💅

👑 SEE ALSO 👑

• install_keyboard(3)
• readkey(3)
• ureadkey(3)
• keyboard_ucallback(3)
• keyboard_lowlevel_callback(3)

and that's a wrap, bestie 🎀 this was Allegro, version 4.4.3, and it lives on the keyboard_callback(3) page. slay, go lock your memory, and stay iconic 🌈💜