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+'\" 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 2024-05-02 "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)