man3/nextup.3

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  25 .TH NEXTUP 3 2016-10-08 "GNU" "Linux Programmer's Manual"
  26 .SH NAME
  27 nextup, nextupf, nextupl, nextdown, nextdownf, nextdownl \-
  28 return next floating-point number toward positive/negative infinity
  29 .SH SYNOPSIS
  30 .nf
  31 .BR "#define _GNU_SOURCE" "     /* See feature_test_macros(7) */"
  32 .B #include <math.h>
  33
  34 .BI "double nextup(double " x );
  35 .BI "float nextupf(float " x );
  36 .BI "long double nextupl(long double " x );
  37
  38 .BI "double nextdown(double " x );
  39 .BI "float nextdownf(float " x );
  40 .BI "long double nextdownl(long double " x );
  41
  42 Link with \fI\-lm\fP.
  43 .SH DESCRIPTION
  44 The
  45 .BR nextup (),
  46 .BR nextupf (),
  47 and
  48 .BR nextupl ()
  49 functions return the next representable floating-point number greater than
  50 .IR x .
  51
  52 If
  53 .I x
  54 is the smallest representable negative number in the corresponding type,
  55 these functions return \-0.
  56 If
  57 .I x
  58 is 0, the returned value is the smallest representable positive number
  59 of the corresponding type.
  60
  61 If
  62 .I x
  63 is positive infinity, the returned value is positive infinity.
  64 If
  65 .I x
  66 is negative infinity,
  67 the returned value is the largest representable finite negative number
  68 of the corresponding type.
  69
  70 If
  71 .I x
  72 is Nan,
  73 the returned value is NaN.
  74
  75 The value returned by
  76 .IR nextdown(x)
  77 is
  78 .IR \-nextup(\-x) ,
  79 and similarly for the other types.
  80 .SH RETURN VALUE
  81 See DESCRIPTION.
  82 .\" .SH ERRORS
  83 .SH VERSIONS
  84 These functions first appeared in glibc in version 2.24.
  85 .SH ATTRIBUTES
  86 For an explanation of the terms used in this section, see
  87 .BR attributes (7).
  88 .TS
  89 allbox;
  90 lbw36 lb lb
  91 l l l.
  92 Interface       Attribute       Value
  93 T{
  94 .BR nextup (),
  95 .BR nextupf (),
  96 .BR nextupl (),
  97 .br
  98 .BR nextdown (),
  99 .BR nextdownf (),
 100 .BR nextdownl ()
 101 T}      Thread safety   MT-Safe
 102 .TE
 103 .SH CONFORMING TO
 104 These functions are described in
 105 .IR "IEEE Std 754-2008 - Standard for Floating-Point Arithmetic"
 106 and
 107 .IR "ISO/IEC TS 18661".
 108 .SH SEE ALSO
 109 .BR nearbyint (3),
 110 .BR nextafter (3)