Copyright (c) 2011 Jukka Ruohonen <jruohonen (at] iki.fi>
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
.Dd September 13, 2015 .Dt NEXTAFTER 3 .Os .Sh NAME .Nm nextafter , .Nm nextafterf , .Nm nextafterl , .Nm nexttoward , .Nm nexttowardf , .Nm nexttowardl .Nd next representable floating-point number .Sh LIBRARY .Lb libm .Sh SYNOPSIS n math.h .Ft double .Fn nextafter "double x" "double y" .Ft float .Fn nextafterf "float x" "float y" .Ft long double .Fn nextafterl "long double x" "long double y" .Ft double .Fn nexttoward "double x" "long double y" .Ft float .Fn nexttowardf "float x" "long double y" .Ft long double .Fn nexttowardl "long double x" "long double y" .Sh DESCRIPTION The .Fn nextafter , .Fn nextafterf , and .Fn nextafterl functions return the next machine representable number from .Fa x in direction of .Fa y . In other words, if .Fa y is less than .Fa x , the functions return the largest representable floating-point number less than .Fa x . When .Fa x equals .Fa y , the value of .Fa y is returned. The three functions differ only in the type of the return value and .Fa x .
p The .Fn nexttoward and .Fn nexttowardf functions are equivalent to the .Fn nextafter family of functions with two exceptions: l -enum -offset indent t The second parameter has a type .Vt long double . t The return value is .Fa y converted to the type of the function, provided that .Fa x equals .Fa y . .El
p .Fn nexttowardl is equivalent to .Fn nextafterl . .Sh RETURN VALUES Upon successful completion, the described functions return the next representable floating-point value as described above. If .Fa x is finite but an overflow would occur, a range error follows and the functions return .Dv \*(PmHUGE_VAL , .Dv \*(PmHUGE_VALF , or .Dv \*(PmHUGE_VALL with the same sign as .Fa x . When either .Fa x or .Fa y is \*(Na, a \*(Na is returned. When .Fa x is not .Fa y but the function value is subnormal, zero, or underflows, a range error occurs, and either 0.0 or the correct function value (if representable) is returned. .Sh SEE ALSO .Xr math 3 .Sh STANDARDS The described functions conform to .St -isoC-99 .
Indexes created Thu Oct 02 14:10:14 GMT 2025