load_datafile_callback(3alleg4)

💾 load_datafile_callback — the Allegro manual page, bestie edition 🎀

okay so we're in the Allegro manual, and today's main character is load_datafile_callback. it's giving "load a whole datafile but also vibe-check every single object on the way in." ✨

🌸 NAME 🌸

load_datafile_callback — loads a datafile into memory, and calls a hook function once per object. yes, per object. the Allegro game programming library said "let's make loading screens cute." 💅

🦋 SYNOPSIS 🦋

#include <allegro.h>

DATAFILE *load_datafile_callback(const char *filename, void
(*callback)(DATAFILE *d));

💖 DESCRIPTION 💖

so basically: it loads a datafile into memory, and along the way it calls the hook function you gave it once for each object in the file, handing that function a pointer to the object it just read. 🫶

why do you care? because this is how you build a very simple loading screen — every time the hook fires, you redraw the screen so the user knows your program is still out here grinding, still reading from disk, not frozen, not ghosting them. 😭

here's the example, verbatim, no notes:

void load_callback(DATAFILE *dat_obj)
{
   static const char indicator[] = "-\\|/-.oOXOo.";
   static int current = 0;

   /* Show a different character every time. */
   textprintf_ex(screen, font, 0, 0, makecol(0, 0, 0),
                 makecol(255, 255, 255), "%c Loading %c",
                 indicator[current], indicator[current]);
   /* Increase index and check if we need to reset it. */
   current++;
   if (!indicator[current])
      current = 0;
}
   ...
   dat = load_datafile_callback("data.dat", load_callback);

the little spinner goes -\|/-.oOXOo. and honestly? iconic. ⭐

✨ RETURN VALUE ✨

returns a pointer to the DATAFILE, or NULL if something went wrong. 🥲

bestie. remember to free this DATAFILE later to avoid memory leaks. leaking memory is not the vibe. 🙈

👑 SEE ALSO 👑

• load_datafile(3alleg4)
• unload_datafile(3alleg4)
• load_datafile_object(3alleg4)
• set_color_conversion(3alleg4)
• fixup_datafile(3alleg4)
• packfile_password(3alleg4)
• find_datafile_object(3alleg4)
• register_datafile_object(3alleg4)

and that's the whole page, fr fr. this was the Allegro manual, version 4.4.3, for load_datafile_callback(3alleg4) — go forth and load responsibly, mwah 💜🌈