NAN(3P)

✨ NAN(3P) — POSIX Programmer's Manual ✨

okay bestie, we're reading the POSIX Programmer's Manual page for NAN(3P) and honestly? it's short, it's sweet, it's giving "quiet" in the most literal way possible 💅

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🌸 PROLOG 🌸

so like, heads up before we even start: this manual page is part of the POSIX Programmer's Manual. the Linux implementation of this interface may differ — so go consult the corresponding Linux manual page for the deets on Linux behavior — or honestly the interface might not even be implemented on Linux at all. not me warning you before you get attached 😭

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👑 NAME 👑

nan, nanf, nanl — return quiet NaN 🫶

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🎀 SYNOPSIS 🎀

#include <math.h>

double nan(const char *tagp);
float nanf(const char *tagp);
long double nanl(const char *tagp);

three besties, three float types, one shared mission ✨

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💖 DESCRIPTION 💖

The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional — like, no drama intended fr fr. This volume of POSIX.1‐2017 defers to the ISO C standard.

now the actual tea 🍓 The function call nan("n-char-sequence") shall be equivalent to:

strtod("NAN(n-char-sequence)", (char **) NULL);

The function call nan("") shall be equivalent to:

strtod("NAN()", (char **) NULL)

If tagp does not point to an n-char sequence or an empty string, the function call shall be equivalent to:

strtod("NAN", (char **) NULL)

and the glow-up continues: Function calls to nanf() and nanl() are equivalent to the corresponding function calls to strtof() and strtold(). slay, consistent family behavior, we love to see it 👑

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🦋 RETURN VALUE 🦋

These functions shall return a quiet NaN, if available, with content indicated through tagp 💫

If the implementation does not support quiet NaNs, these functions shall return zero. yes bestie, zero. no NaN for you. tragic, but that's the spec 😭

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💀 ERRORS 💀

No errors are defined. iconic. nothing to catch, nothing to handle, we're at peace 🧘‍♀️

The following sections are informative. (translation: the lore, not the law 📖)

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🌈 EXAMPLES 🌈

None. not a single one. the void. the silence. very quiet NaN energy fr 🙈

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💜 APPLICATION USAGE 💜

None. same vibe, different heading 💅

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⭐ RATIONALE ⭐

None. the reasoning is simply vibes 🎀

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🔥 FUTURE DIRECTIONS 🔥

None. the future is uncharted and also empty 🦋

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🌸 SEE ALSO 🌸

• strtod()

The Base Definitions volume of POSIX.1‐2017, <math.h>

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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. 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 the whole page bestie, no cap, every last detail preserved 💖 this iconic little number was brought to you by IEEE/The Open Group, 2017 — catch you on the next one, mwah 🫶✨