RINT(3P)

🌸 RINT(3P) — bestie edition 🌸

okay so this is the POSIX Programmer's Manual page for rint, and I'm gonna walk you through it like we're texting at 1am, except every single fact stays exactly where it was. 💖

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✨ PROLOG ✨

real talk before we even start: this manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ — so like, go consult the corresponding Linux manual page for the tea on Linux behavior. Or… it might not be implemented on Linux at all. 🙈 iykyk.

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👑 NAME 👑

rint, rintf, rintl — round-to-nearest integral value. that's the whole vibe, bestie. ✨

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🎀 SYNOPSIS 🎀

#include <math.h>

double rint(double x);
float rintf(float x);
long double rintl(long double x);

three icons, three types, one job. 💅

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🦋 DESCRIPTION 🦋

okay so the functionality described on this reference page is aligned with the ISO C standard. And like, any conflict between the requirements described here and the ISO C standard? Not intentional, promise. This volume of POSIX.1‐2017 defers to the ISO C standard. periodt.

These functions shall return the integral value (represented as a double) nearest x in the direction of the current rounding mode. The current rounding mode is implementation-defined — so it's giving "mystery, but make it standards-compliant." 🧚

Now here's the mood board of rounding modes, bestie:

• If the current rounding mode rounds toward negative infinity, then rint() shall be equivalent to floor().
• If the current rounding mode rounds toward positive infinity, then rint() shall be equivalent to ceil().
• If the current rounding mode rounds towards zero, then rint() shall be equivalent to trunc().
• If the current rounding mode rounds towards nearest, then rint() differs from round() in that halfway cases are rounded to even rather than away from zero. (banker's rounding ate, ngl)

These functions differ from the nearbyint(), nearbyintf(), and nearbyintl() functions only in that they may raise the inexact floating-point exception if the result differs in value from the argument. so like, cousins, not twins. 👯

An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if errno is non-zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred. write that down. 📝

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💖 RETURN VALUE 💖

Upon successful completion, these functions shall return the integer (represented as a double precision number) nearest x in the direction of the current rounding mode. The result shall have the same sign as x. slay.

• If x is NaN, a NaN shall be returned.
• If x is ±0 or ±Inf, x shall be returned. (it said "no notes, I'm already perfect" 💅)

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💀 ERRORS 💀

No errors are defined. iconic behavior honestly.

The following sections are informative. 🫶

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🌈 EXAMPLES 🌈

None. bestie we have no examples. we ball regardless.

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🍓 APPLICATION USAGE 🍓

The integral value returned by these functions need not be expressible as an intmax_t.

The return value should be tested before assigning it to an integer type to avoid the undefined results of an integer overflow. 💀 this is the part where you do NOT just yolo it into an int, okay? test first.

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🧚 RATIONALE 🧚

None. no thoughts, head empty, standard approved.

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⭐ FUTURE DIRECTIONS ⭐

None. the future is unspecified and honestly? that's her main character energy.

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🔥 SEE ALSO 🔥

• abs()
• ceil()
• feclearexcept()
• fetestexcept()
• floor()
• isnan()
• nearbyint()

The Base Definitions volume of POSIX.1‐2017, Section 4.20, Treatment of Error Conditions for Mathematical Functions, <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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okay that's the whole page, you ate that, go round some numbers responsibly 🫶✨

— brought to you by IEEE/The Open Group, 2017, aka the year this page was born. RINT(3P) signing off 💅🎀