explain_vsprintf_or_die(3)

✨ explain_vsprintf_or_die(3) — Library Functions Manual ✨

okay bestie, buckle up, we're doing a libexplain page today 💅 this one lives in section 3 of the manual (the library functions girlies), and it's all about formatting output and then, if things go sideways, telling you why instead of just quietly failing like some coward. no cap.

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🌸 NAME 🌸

explain_vsprintf_or_die — formatted output conversion and report errors 🎀

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🦋 SYNOPSIS 🦋

#include <libexplain/vsprintf.h>
int explain_vsprintf_or_die(char *data, const char *format, va_list ap);
int explain_vsprintf_on_error(char *data, const char *format, va_list
ap);

yes the va_list ap line wraps, that's just how the header page is laid out, don't come for me 🙈

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💖 DESCRIPTION 💖

So. Two functions, two whole vibes:

• explain_vsprintf_or_die is the main character. It's used to call the vsprintf(3) system call. And if that call fails? It prints an explanation to stderr — and that explanation comes from the explain_vsprintf(3) function — and then the process terminates by calling exit(EXIT_FAILURE). like, it does not come back. it's giving "we're done here" 💀
• explain_vsprintf_on_error is the chill one. It's also used to call the vsprintf(3) system call, and on failure it also prints an explanation to stderr obtained from the explain_vsprintf(3) function — but then it still returns to the caller. soft launch failure, no dramatic exit 🫶

now the arguments, bestie, and yes they are literally just "exactly as to be passed to vsprintf(3)":

• data — The data, exactly as to be passed to the vsprintf(3) system call.
• format — The format, exactly as to be passed to the vsprintf(3) system call.
• ap — The ap, exactly as to be passed to the vsprintf(3) system call.

that's it. that's the trio. don't get creative with them, just pass them through like a good little wrapper 🎀

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👑 RETURN VALUE 👑

• explain_vsprintf_or_die only returns on success, see vsprintf(3) for more information. On failure, it prints an explanation and exits — it does not return. nope. gone. not coming back. ✨
• explain_vsprintf_on_error always returns the value return by the wrapped vsprintf(3) system call. (yes, "return" — that's the original wording, we're keeping it fr fr 💜)

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🌈 EXAMPLE 🌈

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

int result = explain_vsprintf_or_die(data, format, ap);

one line. iconic. that's the whole example and honestly? it ate 🔥

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⭐ SEE ALSO ⭐

• vsprintf(3) — formatted output conversion
• explain_vsprintf(3) — explain vsprintf(3) errors
• exit(2) — terminate the calling process

go read those next, iykyk 🦋

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🎀 COPYRIGHT 🎀

libexplain version 1.4 Copyright (C) 2010 Peter Miller

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and that's the whole page, bestie 💖 huge shoutout to libexplain version 1.4 and Copyright (C) 2010 Peter Miller for making the vsprintf errors make sense — this was explain_vsprintf_or_die(3) from the Library Functions Manual, signing off, mwah 💅✨