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diff --git a/man/man3/nextafter.3 b/man/man3/nextafter.3 new file mode 100644 index 000000000..a33c1c4f6 --- /dev/null +++ b/man/man3/nextafter.3 @@ -0,0 +1,200 @@ +'\" t +.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) +.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk +.\" <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: GPL-1.0-or-later +.\" +.\" Based on glibc infopages +.\" +.TH nextafter 3 (date) "Linux man-pages (unreleased)" +.SH NAME +nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl \- +floating-point number manipulation +.SH LIBRARY +Math library +.RI ( libm ", " \-lm ) +.SH SYNOPSIS +.nf +.B #include <math.h> +.P +.BI "double nextafter(double " x ", double " y ); +.BI "float nextafterf(float " x ", float " y ); +.BI "long double nextafterl(long double " x ", long double " y ); +.P +.BI "double nexttoward(double " x ", long double " y ); +.BI "float nexttowardf(float " x ", long double " y ); +.BI "long double nexttowardl(long double " x ", long double " y ); +.fi +.P +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.P +.BR nextafter (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L + || _XOPEN_SOURCE >= 500 +.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED + || /* Since glibc 2.19: */ _DEFAULT_SOURCE + || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE +.fi +.P +.BR nextafterf (), +.BR nextafterl (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L + || /* Since glibc 2.19: */ _DEFAULT_SOURCE + || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE +.fi +.P +.BR nexttoward (), +.BR nexttowardf (), +.BR nexttowardl (): +.nf + _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE + || _POSIX_C_SOURCE >= 200112L +.fi +.SH DESCRIPTION +The +.BR nextafter (), +.BR nextafterf (), +and +.BR nextafterl () +functions return the next representable floating-point value following +.I x +in the direction of +.IR y . +If +.I y +is less than +.IR x , +these functions will return the largest representable number less than +.IR x . +.P +If +.I x +equals +.IR y , +the functions return +.IR y . +.P +The +.BR nexttoward (), +.BR nexttowardf (), +and +.BR nexttowardl () +functions do the same as the corresponding +.BR nextafter () +functions, except that they have a +.I "long double" +second argument. +.SH RETURN VALUE +On success, +these functions return the next representable floating-point value after +.I x +in the direction of +.IR y . +.P +If +.I x +equals +.IR y , +then +.I y +(cast to the same type as +.IR x ) +is returned. +.P +If +.I x +or +.I y +is a NaN, +a NaN is returned. +.P +If +.I x +is finite, +.\" e.g., DBL_MAX +and the result would overflow, +a range error occurs, +and the functions return +.BR HUGE_VAL , +.BR HUGE_VALF , +or +.BR HUGE_VALL , +respectively, with the correct mathematical sign. +.P +If +.I x +is not equal to +.IR y , +and the correct function result would be subnormal, zero, or underflow, +a range error occurs, +and either the correct value (if it can be represented), +or 0.0, is returned. +.SH ERRORS +See +.BR math_error (7) +for information on how to determine whether an error has occurred +when calling these functions. +.P +The following errors can occur: +.TP +Range error: result overflow +.\" e.g., nextafter(DBL_MAX, HUGE_VAL); +.I errno +is set to +.BR ERANGE . +An overflow floating-point exception +.RB ( FE_OVERFLOW ) +is raised. +.TP +Range error: result is subnormal or underflows +.\" e.g., nextafter(DBL_MIN, 0.0); +.I errno +is set to +.BR ERANGE . +An underflow floating-point exception +.RB ( FE_UNDERFLOW ) +is raised. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR nextafter (), +.BR nextafterf (), +.BR nextafterl (), +.BR nexttoward (), +.BR nexttowardf (), +.BR nexttowardl () +T} Thread safety MT-Safe +.TE +.SH STANDARDS +C11, POSIX.1-2008. +.P +This function is defined in IEC 559 (and the appendix with +recommended functions in IEEE 754/IEEE 854). +.SH HISTORY +C99, POSIX.1-2001. +.SH BUGS +In glibc 2.5 and earlier, these functions do not raise an underflow +floating-point +.RB ( FE_UNDERFLOW ) +exception when an underflow occurs. +.P +Before glibc 2.23 +.\" https://www.sourceware.org/bugzilla/show_bug.cgi?id=6799 +these functions did not set +.IR errno . +.SH SEE ALSO +.BR nearbyint (3) |