explain_signalfd_or_die(3)

💖 explain_signalfd_or_die(3) 💖

okay bestie, sit down, hydrate, because we're talking about a Library Functions Manual page and it's genuinely so good. this is the libexplain corner of the universe where syscalls get wrapped in a little bubble of love so that when they go wrong you actually find out why instead of just staring at -1 like 👁️👄👁️

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✨ NAME ✨

explain_signalfd_or_die — create signalable file descriptor and report errors 🦋

🌸 SYNOPSIS 🌸

#include <libexplain/signalfd.h>
int explain_signalfd_or_die(int fildes, const sigset_t *mask, int
flags);
int explain_signalfd_on_error(int fildes, const sigset_t *mask, int
flags);

💅 DESCRIPTION 💅

so, two functions, two whole vibes, both of them are just wrapping the signalfd(2) system call, no cap.

The explain_signalfd_or_die function is used to call the signalfd(2) system call. On failure an explanation will be printed to stderr, obtained from the explain_signalfd(3) function, and then the process terminates by calling exit(EXIT_FAILURE). yeah. it literally dies. that's not a metaphor, that's the function name being extremely honest with you 💀

The explain_signalfd_on_error function is used to call the signalfd(2) system call. On failure an explanation will be printed to stderr, obtained from the explain_signalfd(3) function, but still returns to the caller. so this one is the chill sibling — it tells you what went wrong and then hands the situation back to you like "here, you deal with it, i'm not making that decision for you" 🫶

and now the arguments, bestie, all three of them, exactly as they are:

• fildes — The fildes, exactly as to be passed to the signalfd(2) system call. no extra seasoning, no interpretation, we pass it straight through 👑
• mask — The mask, exactly as to be passed to the signalfd(2) system call. again: verbatim, untouched, icon behaviour ✨
• flags — The flags, exactly as to be passed to the signalfd(2) system call. same energy, same rule 🌈

the pattern here is "exactly as to be passed to the signalfd(2) system call" and that's the whole point — these wrappers don't get creative with your arguments. they hand them over and then handle the aftermath. periodt.

🎀 RETURN VALUE 🎀

The explain_signalfd_or_die function only returns on success, see signalfd(2) for more information. On failure, prints an explanation and exits, it does not return. like, it does not return. if you were waiting for it to come back you're gonna be waiting forever 🙈

The explain_signalfd_on_error function always returns the value return by the wrapped signalfd(2) system call. (yes, "return" — that's what the page says, and we're keeping it fr fr.) so you always get your answer back, good or bad, and it's your problem now 💜

⭐ EXAMPLE ⭐

The explain_signalfd_or_die function is intended to be used in a fashion similar to the following example:

int result = explain_signalfd_or_die(fildes, mask, flags);

one line. that's it. that's the whole demo. lowkey iconic how much chaos one line can prevent 🌸

👑 SEE ALSO 👑

• signalfd(2) — create a file descriptor for accepting signals
• explain_signfd(3) — explain signalfd(2) errors
• exit(2) — terminate the calling process

(okay it's explain_signalfd(3) not explain_signfd(3), my bad, the real one is explain_signalfd(3) — explain signalfd(2) errors 💖)

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💜 COPYRIGHT 💜

libexplain version 1.4 Copyright (C) 2009 Peter Miller

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and that's the whole page, bestie!! 🎀 this gorgeous little manual comes to you from libexplain version 1.4, with copyright belonging to Peter Miller, dating all the way back to 2009 — and yes, explain_signalfd_or_die(3) is the page name you'd look up to find it. go forth and wrap your syscalls, you absolute main character 🦋✨