man3/finite.3

   1 .\" Copyright 2004 Andries Brouwer <aeb@cwi.nl>.
   2 .\"
   3 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   4 .\"
   5 .TH FINITE 3  2021-03-22 "" "Linux Programmer's Manual"
   6 .SH NAME
   7 finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf, isnanl \-
   8 BSD floating-point classification functions
   9 .SH LIBRARY
  10 Math library
  11 .RI ( libm ", " \-lm )
  12 .SH SYNOPSIS
  13 .nf
  14 .B #include <math.h>
  15 .PP
  16 .BI "int finite(double " x );
  17 .BI "int finitef(float " x );
  18 .BI "int finitel(long double " x );
  19 .PP
  20 .BI "int isinf(double " x );
  21 .BI "int isinff(float " x );
  22 .BI "int isinfl(long double " x );
  23 .PP
  24 .BI "int isnan(double " x );
  25 .BI "int isnanf(float " x );
  26 .BI "int isnanl(long double " x );
  27 .fi
  28 .PP
  29 .RS -4
  30 Feature Test Macro Requirements for glibc (see
  31 .BR feature_test_macros (7)):
  32 .RE
  33 .PP
  34 .BR finite (),
  35 .BR finitef (),
  36 .BR finitel ():
  37 .nf
  38     /* Glibc since 2.19: */ _DEFAULT_SOURCE
  39         || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  40 .PP
  41 .BR isinf ():
  42     _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE
  43         || /* Glibc since 2.19: */ _DEFAULT_SOURCE
  44         || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  45 .fi
  46 .PP
  47 .BR isinff (),
  48 .BR isinfl ():
  49 .nf
  50     /* Glibc since 2.19: */ _DEFAULT_SOURCE
  51         || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  52 .fi
  53 .PP
  54 .BR isnan ():
  55 .nf
  56     _XOPEN_SOURCE || _ISOC99_SOURCE
  57         || /* Glibc since 2.19: */ _DEFAULT_SOURCE
  58         || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  59 .fi
  60 .PP
  61 .BR isnanf (),
  62 .BR isnanl ():
  63 .nf
  64     _XOPEN_SOURCE >= 600
  65         || /* Glibc since 2.19: */ _DEFAULT_SOURCE
  66         || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  67 .fi
  68 .SH DESCRIPTION
  69 The
  70 .BR finite (),
  71 .BR finitef (),
  72 and
  73 .BR finitel ()
  74 functions return a nonzero value if
  75 .I x
  76 is neither infinite
  77 nor a "not-a-number" (NaN) value, and 0 otherwise.
  78 .PP
  79 The
  80 .BR isnan (),
  81 .BR isnanf (),
  82 and
  83 .BR isnanl ()
  84 functions return a nonzero value if
  85 .I x
  86 is a NaN value,
  87 and 0 otherwise.
  88 .PP
  89 The
  90 .BR isinf (),
  91 .BR isinff (),
  92 and
  93 .BR isinfl ()
  94 functions return 1 if
  95 .I x
  96 is positive infinity, \-1 if
  97 .I x
  98 is negative infinity, and 0 otherwise.
  99 .SH ATTRIBUTES
 100 For an explanation of the terms used in this section, see
 101 .BR attributes (7).
 102 .ad l
 103 .nh
 104 .TS
 105 allbox;
 106 lbx lb lb
 107 l l l.
 108 Interface       Attribute       Value
 109 T{
 110 .BR finite (),
 111 .BR finitef (),
 112 .BR finitel (),
 113 .BR isinf (),
 114 .BR isinff (),
 115 .BR isinfl (),
 116 .BR isnan (),
 117 .BR isnanf (),
 118 .BR isnanl ()
 119 T}      Thread safety   MT-Safe
 120 .TE
 121 .hy
 122 .ad
 123 .sp 1
 124 .SH NOTES
 125 Note that these functions are obsolete.
 126 C99 defines macros
 127 .BR isfinite (),
 128 .BR isinf (),
 129 and
 130 .BR isnan ()
 131 (for all types) replacing them.
 132 Further note that the C99
 133 .BR isinf ()
 134 has weaker guarantees on the return value.
 135 See
 136 .BR fpclassify (3).
 137 .\"
 138 .\" finite* not on HP-UX; they exist on Tru64.
 139 .\" .SH HISTORY
 140 .\" The
 141 .\" .BR finite ()
 142 .\" function occurs in 4.3BSD.
 143 .\" see IEEE.3 in the 4.3BSD manual
 144 .SH SEE ALSO
 145 .BR fpclassify (3)