| .\" Copyright 2001 Andries Brouwer <aeb@cwi.nl>. |
| .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk |
| .\" <mtk.manpages@gmail.com> |
| .\" |
| .\" %%%LICENSE_START(VERBATIM) |
| .\" Permission is granted to make and distribute verbatim copies of this |
| .\" manual provided the copyright notice and this permission notice are |
| .\" preserved on all copies. |
| .\" |
| .\" Permission is granted to copy and distribute modified versions of this |
| .\" manual under the conditions for verbatim copying, provided that the |
| .\" entire resulting derived work is distributed under the terms of a |
| .\" permission notice identical to this one. |
| .\" |
| .\" Since the Linux kernel and libraries are constantly changing, this |
| .\" manual page may be incorrect or out-of-date. The author(s) assume no |
| .\" responsibility for errors or omissions, or for damages resulting from |
| .\" the use of the information contained herein. The author(s) may not |
| .\" have taken the same level of care in the production of this manual, |
| .\" which is licensed free of charge, as they might when working |
| .\" professionally. |
| .\" |
| .\" Formatted or processed versions of this manual, if unaccompanied by |
| .\" the source, must acknowledge the copyright and authors of this work. |
| .\" %%%LICENSE_END |
| .\" |
| .TH RINT 3 2017-09-15 "" "Linux Programmer's Manual" |
| .SH NAME |
| nearbyint, nearbyintf, nearbyintl, rint, rintf, rintl \- round |
| to nearest integer |
| .SH SYNOPSIS |
| .nf |
| .B #include <math.h> |
| .PP |
| .BI "double nearbyint(double " x ); |
| .BI "float nearbyintf(float " x ); |
| .BI "long double nearbyintl(long double " x ); |
| .PP |
| .BI "double rint(double " x ); |
| .BI "float rintf(float " x ); |
| .BI "long double rintl(long double " x ); |
| .fi |
| .PP |
| Link with \fI\-lm\fP. |
| .PP |
| .in -4n |
| Feature Test Macro Requirements for glibc (see |
| .BR feature_test_macros (7)): |
| .in |
| .PP |
| .ad l |
| .BR nearbyint (), |
| .BR nearbyintf (), |
| .BR nearbyintl (): |
| .RS 4 |
| _POSIX_C_SOURCE\ >=\ 200112L || _ISOC99_SOURCE |
| .RE |
| .br |
| .BR rint (): |
| .RS 4 |
| _ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L |
| || _XOPEN_SOURCE\ >=\ 500 |
| .\" || _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED |
| || /* Since glibc 2.19: */ _DEFAULT_SOURCE |
| || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE |
| .RE |
| .br |
| .BR rintf (), |
| .BR rintl (): |
| .RS 4 |
| _ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L |
| || /* Since glibc 2.19: */ _DEFAULT_SOURCE |
| || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE |
| .RE |
| .ad b |
| .SH DESCRIPTION |
| The |
| .BR nearbyint (), |
| .BR nearbyintf (), |
| and |
| .BR nearbyintl () |
| functions round their argument to an integer value in floating-point |
| format, using the current rounding direction (see |
| .BR fesetround (3)) |
| and without raising the |
| .I inexact |
| exception. |
| When the current rounding direction is to nearest, these |
| functions round halfway cases to the even integer in accordance with |
| IEEE-754. |
| .PP |
| The |
| .BR rint (), |
| .BR rintf (), |
| and |
| .BR rintl () |
| functions do the same, but will raise the |
| .I inexact |
| exception |
| .RB ( FE_INEXACT , |
| checkable via |
| .BR fetestexcept (3)) |
| when the result differs in value from the argument. |
| .SH RETURN VALUE |
| These functions return the rounded integer value. |
| .PP |
| If |
| .I x |
| is integral, +0, \-0, NaN, or infinite, |
| .I x |
| itself is returned. |
| .SH ERRORS |
| No errors occur. |
| POSIX.1-2001 documents a range error for overflows, but see NOTES. |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .TS |
| allbox; |
| lbw26 lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR nearbyint (), |
| .BR nearbyintf (), |
| .br |
| .BR nearbyintl (), |
| .BR rint (), |
| .br |
| .BR rintf (), |
| .BR rintl () |
| T} Thread safety MT-Safe |
| .TE |
| .SH CONFORMING TO |
| C99, POSIX.1-2001, POSIX.1-2008. |
| .SH NOTES |
| SUSv2 and POSIX.1-2001 contain text about overflow (which might set |
| .I errno |
| to |
| .BR ERANGE , |
| or raise an |
| .B FE_OVERFLOW |
| exception). |
| In practice, the result cannot overflow on any current machine, |
| so this error-handling stuff is just nonsense. |
| (More precisely, overflow can happen only when the maximum value |
| of the exponent is smaller than the number of mantissa bits. |
| For the IEEE-754 standard 32-bit and 64-bit floating-point numbers |
| the maximum value of the exponent is 128 (respectively, 1024), |
| and the number of mantissa bits is 24 (respectively, 53).) |
| .PP |
| If you want to store the rounded value in an integer type, |
| you probably want to use one of the functions described in |
| .BR lrint (3) |
| instead. |
| .SH SEE ALSO |
| .BR ceil (3), |
| .BR floor (3), |
| .BR lrint (3), |
| .BR round (3), |
| .BR trunc (3) |