io_fd(3)

💅 io_fd — bestie's guide to prepping a descriptor 💅

okay so. welcome to io_fd, a lil function from libowfat's io family (that's the Library Functions Manual, for the record). its whole job? getting a descriptor ready so io_wait knows you care about it. that's it. that's the girl. ✨

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✨ SYNOPSIS ✨

#include <libowfat/io.h>

int io_fd(int64 fd);

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🌸 DESCRIPTION 🌸

so here's the tea, bestie. if you wanna use io_canread() and io_canwrite() on a descriptor, you have to run io_wait() on it first — and io_wait() has to actually know which descriptors you're interested in. that's where io_fd() comes in. it tells io_wait() "hey, i'm interested in this fd, keep an eye on her." 👀

now, if you already know the descriptor is writable, call io_fd_canwrite() instead. most fresh descriptors are writable, like if it came from pipe(2) or socketpair(2) or accept(2). doing that saves you one syscall, and saving syscalls is lowkey self-care. 💖

also, io_pipe and io_socketpair already call io_fd_canwrite() for you, so you don't gotta do a thing. they got you. 🫶

⚠️ okay important part, no skipping: waiting on descriptors only works for sockets, fifos and pipes. it may also work on devices and TTYs, but that's platform dependent — do not rely on that, fr fr. and it does not work on files. like, at all. don't even try it, it's giving disappointment. 💀

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🔥 RETURN VALUE 🔥

• io_fd returns 1 on success, and 0 on error.

that's it. binary queen. 👑

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👑 SEE ALSO 👑

• io_fd_canwrite(3)
• io_wait(3)
• io_wantread(3)
• io_canread(3)
• io_eagain(3)
• io_nonblock(3)

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and that's the whole page, bestie — this was io_fd(3) from the Library Functions Manual (the libowfat crew, no cap), and there's no version or date info on this one so i can't spill what i don't have 🙈. now go forth and prep those descriptors. slay. 💅✨🎀🦋