DEVCLASS_GET_MAXUNIT(9)

💅 DEVCLASS_GET_MAXUNIT — kernel developer's manual, but make it make sense

okay bestie, so this is a page from the Kernel Developer's Manual, and the function we're stanning today is devclass_get_maxunit. it's giving "small function, big confusion" energy, but don't worry — we're gonna get through it together 🫶

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✨ NAME ✨

devclass_get_maxunit — find the maximum unit number in the class 🔢

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🎀 SYNOPSIS 🎀

#include <sys/param.h>
#include <sys/bus.h>

int
devclass_get_maxunit(devclass_t dc);

so you include those two headers, and then you call it with a devclass_t dc. that's the whole vibe. 🦋

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🌸 DESCRIPTION 🌸

okay so here's the tea ☕ — this function returns the next unit number to be allocated to device instances in the devclass.

and like, read that carefully bestie: it's one greater than the highest currently allocated unit. not the highest one, the one after the highest one. the way that's a whole plot twist, i know 😭

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💖 RETURN VALUES 💖

• if dc is NULL, it returns -1 🙈
• otherwise, it returns the next unit number in dc's devclass ✨

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🧚 ERRORS 🧚

None. literally none. not a single one. slay 💅

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🔥 SEE ALSO 🔥

• devclass(9)
• device(9)

go read those too, iykyk 👑

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👑 AUTHORS 👑

this manual page was written by Doug Rabson. iconic behavior, thank you Doug 🫶

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💀 BUGS 💀

okay so the name is confusing, because it's actually one greater than the maximum unit 😭 like the naming committee really said "let's make it a little evil" and honestly? it's giving misleading. so just remember: it's not the max, it's max + 1. periodt. 🌈

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ngl, this one's tiny but the name will absolutely trip you up if you don't read the BUGS section. so like… read it. please. for me. 🎀

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and that's the whole page, bestie! this one came from the Debian flavor of the Kernel Developer's Manual, dated September 10, 2010, and it's the DEVCLASS_GET_MAXUNIT(9) page — go forth and allocate responsibly 💜⭐