SIGNBIT(3P)

💅 signbit(3P) — bestie edition ✨

okay so this is a page from the POSIX Programmer's Manual, and we're doing SIGNBIT(3P) today. yes the title has the manual name in it, we're not typing the whole header line again, you're welcome 🎀

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🌸 PROLOG 🌸

This manual page is part of the POSIX Programmer's Manual, bestie. Two things you need to know before we go any further:

• The Linux implementation of this interface may differ from what's written here — so go check the corresponding Linux manual page for the deets on Linux behavior 👀
• or, plot twist, the interface might not be implemented on Linux at all 💀

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✨ NAME ✨

signbit — test sign. that's it, that's the whole job 🫶

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🦋 SYNOPSIS 🦋

#include <math.h>

int signbit(real-floating x);

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💖 DESCRIPTION 💖

The functionality described on this reference page is aligned with the ISO C standard. And like, if there's any conflict between the requirements described here and the ISO C standard? That conflict is unintentional, no cap. This volume of POSIX.1‐2017 defers to the ISO C standard, periodt.

The signbit() macro shall determine whether the sign of its argument value is negative.

And here's the iconic part: NaNs, zeros, and infinities have a sign bit. yes even zero. yes even NaN. every single one of them is out here carrying a sign bit like it's a little handbag 👑✨

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🔥 RETURN VALUE 🔥

The signbit() macro shall return a non-zero value if and only if the sign of its argument value is negative.

if and only if, bestie. that's a two-way street. no fuzzy vibes here 💅

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🌈 ERRORS 🌈

No errors are defined.

The following sections are informative. (translation: the lore drops from here on, not the rules 📖)

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🍓 EXAMPLES 🍓

None.

ngl there's just nothing here 🙈

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🧚 APPLICATION USAGE 🧚

None.

also nothing. the void is empty. we move 💜

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⭐ RATIONALE ⭐

None.

no reasoning given, it simply is ✨

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💀 FUTURE DIRECTIONS 💀

None.

the future is unwritten and also this page says nothing about it 🌸

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👑 SEE ALSO 👑

• fpclassify()
• isfinite()
• isinf()
• isnan()
• isnormal()

The Base Definitions volume of POSIX.1‐2017, <math.h> — the whole float-classification girl group, go say hi to all of them 🫶

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💜 COPYRIGHT 💜

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group.

In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document (it's the main character, it decides). The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

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and that's a wrap, bestie 🎀 this whole thing was served up by IEEE/The Open Group, dated 2017, for the SIGNBIT(3P) page — slay, ate, no crumbs, periodt 💅✨🦋