1 .\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
2 .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
3 .\" <mtk.manpages@gmail.com>
5 .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
6 .\" Distributed under GPL
9 .\" Based on glibc infopages
11 .TH NEXTAFTER 3 2013-09-02 "GNU" "Linux Programmer's Manual"
13 nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl \-
14 floating-point number manipulation
18 .BI "double nextafter(double " x ", double " y );
20 .BI "float nextafterf(float " x ", float " y );
22 .BI "long double nextafterl(long double " x ", long double " y );
24 .BI "double nexttoward(double " x ", long double " y );
26 .BI "float nexttowardf(float " x ", long double " y );
28 .BI "long double nexttowardl(long double " x ", long double " y );
33 Feature Test Macro Requirements for glibc (see
34 .BR feature_test_macros (7)):
40 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
41 _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED ||
43 _POSIX_C_SOURCE\ >=\ 200112L;
52 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
53 _POSIX_C_SOURCE\ >=\ 200112L;
63 _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
64 _POSIX_C_SOURCE\ >=\ 200112L;
76 functions return the next representable floating-point value following
84 these functions will return the largest representable number less than
99 functions do the same as the corresponding
101 functions, except that they have a
106 these functions return the next representable floating-point value after
117 (cast to the same type as
132 and the result would overflow,
133 a range error occurs,
134 and the functions return
139 respectively, with the correct mathematical sign.
145 and the correct function result would be subnormal, zero, or underflow,
146 a range error occurs,
147 and either the correct value (if it can be represented),
152 for information on how to determine whether an error has occurred
153 when calling these functions.
155 The following errors can occur:
157 Range error: result overflow
158 .\" e.g., nextafter(DBL_MAX, HUGE_VAL);
162 An overflow floating-point exception
166 Range error: result is subnormal or underflows
167 .\" e.g., nextafter(DBL_MIN, 0.0);
171 An underflow floating-point exception
175 These functions do not set
177 .\" FIXME . Is it intentional that these functions do not set errno?
178 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6799
180 .SS Multithreading (see pthreads(7))
189 functions are thread-safe.
192 This function is defined in IEC 559 (and the appendix with
193 recommended functions in IEEE 754/IEEE 854).
195 In glibc version 2.5 and earlier, these functions do not raise an underflow
198 exception when an underflow occurs.
202 This page is part of release 3.67 of the Linux
205 A description of the project,
206 information about reporting bugs,
207 and the latest version of this page,
209 \%http://www.kernel.org/doc/man\-pages/.