fixdiv(3)

💖 fixdiv(3) — the Allegro manual, but make it make sense 💖

ok so bestie, welcome to the Allegro manual page for fixdiv. yes that Allegro. the game programming library. we're doing fixed point math today and honestly? it's giving ✨precision✨

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🌸 SYNOPSIS 🌸

#include <allegro.h>

fixed fixdiv(fixed x, fixed y);

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🦋 DESCRIPTION 🦋

okay so here's the tea. 🫖

A fixed point value can be divided by an integer using the normal / operator. easy. no drama.

But dividing two fixed point values?? nope, that's not a vibe. for that you must use this function. fixdiv is the main character here. 👑

💀 the scary part: if a division by zero happens, errno gets set and the maximum possible value gets returned. BUT — and this is the sneaky bit — errno is not cleared if the operation is successful. so if you're tryna test for division by zero, you gotta set errno=0 before calling fixdiv(). no cap.

Example, because seeing it is believing:

fixed result;
/* This will put 0.06060 `result'. */
result = fixdiv(itofix(2), itofix(33));
/* This will put 0 into `result'. */
result = fixdiv(0, itofix(-30));
/* Sets `errno' and puts -32768 into `result'. */
result = fixdiv(itofix(-100), itofix(0));
ASSERT(!errno); /* This will fail. */

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✨ RETURN VALUE ✨

Returns the result of dividing x by y. simple. slay. 💅

But if y is zero? it returns the maximum possible fixed point value and sets errno to ERANGE. so like, it doesn't crash on you, it just hands you the biggest number it has and a little note about it. iconic behaviour honestly 🎀

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🎀 SEE ALSO 🎀

• fixadd(3)
• fixsub(3)
• fixmul(3)
• exfixed(3)

the whole fixed-point friend group fr fr 🫶

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and that's the page!! this was the Allegro manual, version 4.4.3 — shoutout to the Allegro girlies who wrote it, mwah, go divide something responsibly bestie, and remember: set errno=0 first or you WILL be confused. 😭✨💖