explain_getpgrp_or_die(3)

💖 explain_getpgrp_or_die(3) — Library Functions Manual 💖

okay bestie, gather round, because today we're talking about explain_getpgrp_or_die — the lil glow-up wrapper that grabs a process group for you and then actually tells you what went wrong if it doesn't work. no silent failures in this house. ✨

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🌸 NAME 🌸

explain_getpgrp_or_die — get process group and report errors

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🎀 SYNOPSIS 🎀

#include <libexplain/getpgrp.h>
pid_t explain_getpgrp_or_die(pid_t pid);
pid_t explain_getpgrp_on_error(pid_t pid);

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✨ DESCRIPTION ✨

So here's the vibe. explain_getpgrp_or_die is the function you call when you want to hit up the getpgrp(2) system call. If it works? adorable, slay. If it fails? it prints an explanation over to stderr — and that explanation comes from the explain_getpgrp(3) function, which is literally its whole job — and then the process terminates by calling exit(EXIT_FAILURE). like, it's not coming back. it does not return. periodt. 💀

Then there's explain_getpgrp_on_error, the softer sibling. it also calls the getpgrp(2) system call, and on failure it also prints that explanation to stderr (again, sourced from explain_getpgrp(3)), but this one is polite — it still returns to the caller. 🫶

• pid — the pid, exactly as to be passed to the getpgrp(2) system call.

🌈 API Inconsistencies 🌈

okay so heads up, this is the messy part and it's not our fault: getpgrp(2) has two implementations. the POSIX.1 version takes no arguments, and the BSD version takes one argument. for simplicity of implementation, the argument list you see up there includes the pid argument.

you can get the POSIX.1 getpgid() semantics by calling getpgrp(0) on BSD systems — and that right there is the API for libexplain, even on systems that do not use the BSD API. iykyk. 💅

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👑 RETURN VALUE 👑

explain_getpgrp_or_die only returns on success — peep getpgrp(2) for more info on that. on failure it prints an explanation and exits, so like… it does not return. at all. that's the deal. 😭

explain_getpgrp_on_error always returns the value returned by the wrapped getpgrp(2) system call. always. no cap.

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🦋 EXAMPLE 🦋

the intended vibe for explain_getpgrp_or_die is something like this:

pid_t result = explain_getpgrp_or_die(pid);

that's it. that's the whole thing. chef's kiss. 🔥

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💜 SEE ALSO 💜

• getpgrp(2) — get process group
• explain_getpgrp(3) — explain getpgrp(2) errors
• exit(2) — terminate the calling process

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🌟 COPYRIGHT 🌟

libexplain version 1.4 Copyright (C) 2011 Peter Miller

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and that's the whole page, bestie 🎀 this was libexplain version 1.4, copyrighted 2011 by Peter Miller, and the manual page itself is explain_getpgrp_or_die(3) from the Library Functions Manual — mwah, go forth and check your return values 💖✨🌸