ISNORMAL(3POSIX)

💖 ISNORMAL(3POSIX) — the POSIX Programmer's Manual one 💖

okay bestie, welcome to the POSIX Programmer's Manual entry for isnormal, and yes it lives in section 3POSIX because that's just how the girls do it. 🌸

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✨ PROLOG ✨

so like, real talk first 🫶 — this manual page is part of the POSIX Programmer's Manual. But heads up: the Linux implementation of this interface may differ, so if you're on Linux you should go consult the corresponding Linux manual page for the details of how Linux actually behaves. Or — plot twist — the interface might not even be implemented on Linux at all. 🙈 iykyk.

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🌈 NAME 🌈

isnormal — the girl whose whole job is testing for a normal value 💅

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🎀 SYNOPSIS 🎀

#include <math.h>

int isnormal(real-floating x);

she's a macro, she's short, she's iconic. periodt.

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🦋 DESCRIPTION 🦋

okay so first things first, the functionality described on this reference page is aligned with the ISO C standard. If anything here conflicts with the requirements in the ISO C standard, that conflict is unintentional — no drama intended. And this volume of POSIX.1‐2017 defers to the ISO C standard, so like, the ISO C standard is the main character here. 👑

now the actual tea ☕: the isnormal() macro shall determine whether its argument value is normal — and "normal" means it's neither zero, subnormal, infinite, nor NaN. that's the whole vibe check. ✨

first, an argument that's represented in a format wider than its semantic type gets converted to its semantic type. then the determination is based on the type of the argument. so it's convert first, judge second. 🧚

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⭐ RETURN VALUE ⭐

the isnormal() macro shall return a non-zero value if and only if its argument has a normal value. no in-between, no maybe, it's giving binary. 💀

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💜 ERRORS 💜

No errors are defined. (she simply does not do errors, bestie 🫶)

the following sections are informative. so like, they're the bonus content, not the rules. 📖

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🍓 EXAMPLES 🍓

None.

(i know, i know, we were all hoping for a lil demo 😭 but there's literally none here.)

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🌸 APPLICATION USAGE 🌸

None.

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🔥 RATIONALE 🔥

None.

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👑 FUTURE DIRECTIONS 👑

None.

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🌈 SEE ALSO 🌈

• fpclassify()
• isfinite()
• isinf()
• isnan()
• signbit()

and also, from the Base Definitions volume of POSIX.1‐2017:

• <math.h>

the whole friend group, fr fr. 🫶

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💅 COPYRIGHT 💅

okay legal era, gotta be precise here bestie, no paraphrasing allowed:

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. 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 .

⚠️ also a lil reminder from the top of the page: this manual page is part of the POSIX Programmer's Manual, and the Linux implementation of this interface may differ — so consult the corresponding Linux manual page for details of Linux behavior, or accept that the interface may not be implemented on Linux. no cap.

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and that's the whole page, bestie 💖 slay, you read a manpage, main character behavior honestly. this lil masterpiece came to you from IEEE/The Open Group, dated 2017, filed under ISNORMAL(3POSIX). go forth and vibe check your floats. 🌈✨🎀