FPCLASSIFY(3POSIX)

📦 version 2017a, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu resolute, ubuntu stonking

💅 FPCLASSIFY(3POSIX) — bestie edition

okay so real talk, this is fpclassify from the POSIX Programmer's Manual, and it's giving ✨float detective energy✨. Buckle up, we're classifying numbers.

🌸 PROLOG

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

fr fr, that second part matters — Linux might do its own thing, or this might not even exist on Linux at all. don't come for me, come for the Linux man page. 💀

🎀 NAME

fpclassify — classify real floating type

(it looks at your float and tells you what kind of number it is. main character behavior, honestly.)

✨ SYNOPSIS

#include <math.h>

int fpclassify(real-floating x);

🦋 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. This volume of POSIX.1‐2017 defers to the ISO C standard.

The fpclassify() macro shall classify its argument value as NaN, infinite, normal, subnormal, zero, or into another implementation-defined category. 💖

First, an argument represented in a format wider than its semantic type is converted to its semantic type. Then classification is based on the type of the argument.

so it's literally: shrink your fancy wide float down to its semantic type first, then vibe check it. periodt.

🔥 RETURN VALUE

The fpclassify() macro shall return the value of the number classification macro appropriate to the value of its argument.

(aka it hands you back the matching classification macro. no drama, no surprises. 🫶)

💀 ERRORS

No errors are defined.

The following sections are informative.

🌈 EXAMPLES

None.

🍓 APPLICATION USAGE

None.

🧚 RATIONALE

None.

⭐ FUTURE DIRECTIONS

None.

👑 SEE ALSO

  • isfinite()
  • isinf()
  • isnan()
  • isnormal()
  • signbit()

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

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 .

and that's the whole page bestie, tysm for reading 💖 this iconic lil number-classifier moment was brought to you by IEEE/The Open Group, 2017 — yeah, that footer up there, it's them. mwah. 🎀✨

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