CTOD(9)

✨ NAME ✨

ctod — macros related to bytes, pages, and disk blocks. okay bestie, this is the ctod(9) page from the Kernel Developer’s Manual, and it’s lowkey your cheat sheet for all those conversions 💅

🌸 SYNOPSIS 🌸

#include <sys/param.h>

size
ctod(size x);

size
dtoc(size x);

size
ctob(size x);

size
btoc(size x);

size
dbtob(size x);

size
btodb(size x);

🦋 DESCRIPTION 🦋

The ctod family of macros can be used to convert between bytes, pages (“clicks”), and disk blocks. yes, pages are literally nicknamed “clicks” here — iykyk ✨

The possible conversions are giving a whole map, bestie — no cap, every single one:

• ctod() — from pages to disk blocks
• dtoc() — from disk blocks to pages
• ctob() — from pages to bytes
• btoc() — from bytes to pages
• dbtob() — from disk blocks to bytes
• btodb() — from bytes to disk blocks

These are typical macros that may appear with different names in other operating systems. Examples include btop() and btopr() in Solaris. not me spotting a crossover episode 🌈

💖 SEE ALSO 💖

• param(3) — go peek at this too, bestie 🫶

🎀 HISTORY 🎀

Some of these macros appeared in Version 7 AT&T UNIX. periodt — vintage icon behavior 👑

💀 CAVEATS 💀

bestie, hear me: the described macros make no assumptions about the type of the input parameter. A caller should ensure that neither integer overflow nor integer underflow are possible. fr fr, do your vibe check on the numbers before you send them 💀

💖 that’s the whole page, bestie — Debian, April 8, 2011, CTOD(9) signing off! 💖