man3/nextup.3

   1 '\" t
   2 .\" Copyright (C) 2016, Michael Kerrisk <mtk.manpages@gmail.com>
   3 .\"
   4 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   5 .\"
   6 .TH nextup 3 (date) "Linux man-pages (unreleased)"
   7 .SH NAME
   8 nextup, nextupf, nextupl, nextdown, nextdownf, nextdownl \-
   9 return next floating-point number toward positive/negative infinity
  10 .SH LIBRARY
  11 Math library
  12 .RI ( libm ", " \-lm )
  13 .SH SYNOPSIS
  14 .nf
  15 .BR "#define _GNU_SOURCE" "     /* See feature_test_macros(7) */"
  16 .B #include <math.h>
  17 .PP
  18 .BI "double nextup(double " x );
  19 .BI "float nextupf(float " x );
  20 .BI "long double nextupl(long double " x );
  21 .PP
  22 .BI "double nextdown(double " x );
  23 .BI "float nextdownf(float " x );
  24 .BI "long double nextdownl(long double " x );
  25 .fi
  26 .SH DESCRIPTION
  27 The
  28 .BR nextup (),
  29 .BR nextupf (),
  30 and
  31 .BR nextupl ()
  32 functions return the next representable floating-point number greater than
  33 .IR x .
  34 .PP
  35 If
  36 .I x
  37 is the smallest representable negative number in the corresponding type,
  38 these functions return \-0.
  39 If
  40 .I x
  41 is 0, the returned value is the smallest representable positive number
  42 of the corresponding type.
  43 .PP
  44 If
  45 .I x
  46 is positive infinity, the returned value is positive infinity.
  47 If
  48 .I x
  49 is negative infinity,
  50 the returned value is the largest representable finite negative number
  51 of the corresponding type.
  52 .PP
  53 If
  54 .I x
  55 is Nan,
  56 the returned value is NaN.
  57 .PP
  58 The value returned by
  59 .I nextdown(x)
  60 is
  61 .IR \-nextup(\-x) ,
  62 and similarly for the other types.
  63 .SH RETURN VALUE
  64 See DESCRIPTION.
  65 .\" .SH ERRORS
  66 .SH ATTRIBUTES
  67 For an explanation of the terms used in this section, see
  68 .BR attributes (7).
  69 .ad l
  70 .nh
  71 .TS
  72 allbox;
  73 lbx lb lb
  74 l l l.
  75 Interface       Attribute       Value
  76 T{
  77 .BR nextup (),
  78 .BR nextupf (),
  79 .BR nextupl (),
  80 .BR nextdown (),
  81 .BR nextdownf (),
  82 .BR nextdownl ()
  83 T}      Thread safety   MT-Safe
  84 .TE
  85 .hy
  86 .ad
  87 .sp 1
  88 .SH STANDARDS
  89 These functions are described in
  90 .I IEEE Std 754-2008 - Standard for Floating-Point Arithmetic
  91 and
  92 .IR "ISO/IEC TS 18661".
  93 .SH HISTORY
  94 glibc 2.24.
  95 .SH SEE ALSO
  96 .BR nearbyint (3),
  97 .BR nextafter (3)