man3/finite.3

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  25 .TH FINITE 3  2016-03-15 "" "Linux Programmer's Manual"
  26 .SH NAME
  27 finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf, isnanl \-
  28 BSD floating-point classification functions
  29 .SH SYNOPSIS
  30 .nf
  31 .B #include <math.h>
  32 .PP
  33 .BI "int finite(double " x );
  34 .br
  35 .BI "int finitef(float " x );
  36 .br
  37 .BI "int finitel(long double " x );
  38 .PP
  39 .BI "int isinf(double " x );
  40 .br
  41 .BI "int isinff(float " x );
  42 .br
  43 .BI "int isinfl(long double " x );
  44 .PP
  45 .BI "int isnan(double " x );
  46 .br
  47 .BI "int isnanf(float " x );
  48 .br
  49 .BI "int isnanl(long double " x );
  50 .fi
  51 .PP
  52 .in -4n
  53 Feature Test Macro Requirements for glibc (see
  54 .BR feature_test_macros (7)):
  55 .in
  56 .PP
  57 .ad l
  58 .BR finite (),
  59 .BR finitef (),
  60 .BR finitel ():
  61 .RS 4
  62 /* Glibc since 2.19: */ _DEFAULT_SOURCE
  63     || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  64 .RE
  65 .BR isinf ():
  66 .RS 4
  67 _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE
  68     || /* Glibc since 2.19: */ _DEFAULT_SOURCE
  69     || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  70 .RE
  71 .br
  72 .BR isinff (),
  73 .BR isinfl ():
  74 .RS 4
  75 /* Glibc since 2.19: */ _DEFAULT_SOURCE
  76     || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  77 .RE
  78 .BR isnan ():
  79 .RS 4
  80 _XOPEN_SOURCE || _ISOC99_SOURCE
  81     || /* Glibc since 2.19: */ _DEFAULT_SOURCE
  82     || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  83 .RE
  84 .BR isnanf (),
  85 .BR isnanl ():
  86 .RS 4
  87 _XOPEN_SOURCE\ >=\ 600
  88     || /* Glibc since 2.19: */ _DEFAULT_SOURCE
  89     || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  90 .RE
  91 .ad b
  92 .SH DESCRIPTION
  93 The
  94 .BR finite (),
  95 .BR finitef (),
  96 and
  97 .BR finitel ()
  98 functions return a nonzero value if
  99 .I x
 100 is neither infinite
 101 nor a "not-a-number" (NaN) value, and 0 otherwise.
 102 .PP
 103 The
 104 .BR isnan (),
 105 .BR isnanf (),
 106 and
 107 .BR isnanl ()
 108 functions return a nonzero value if
 109 .I x
 110 is a NaN value,
 111 and 0 otherwise.
 112 .PP
 113 The
 114 .BR isinf (),
 115 .BR isinff (),
 116 and
 117 .BR isinfl ()
 118 functions return 1 if
 119 .I x
 120 is positive infinity, \-1 if
 121 .I x
 122 is negative infinity, and 0 otherwise.
 123 .SH ATTRIBUTES
 124 For an explanation of the terms used in this section, see
 125 .BR attributes (7).
 126 .TS
 127 allbox;
 128 lbw31 lb lb
 129 l l l.
 130 Interface       Attribute       Value
 131 T{
 132 .BR finite (),
 133 .BR finitef (),
 134 .BR finitel (),
 135 .br
 136 .BR isinf (),
 137 .BR isinff (),
 138 .BR isinfl (),
 139 .br
 140 .BR isnan (),
 141 .BR isnanf (),
 142 .BR isnanl ()
 143 T}      Thread safety   MT-Safe
 144 .TE
 145 .SH NOTES
 146 Note that these functions are obsolete.
 147 C99 defines macros
 148 .BR isfinite (),
 149 .BR isinf (),
 150 and
 151 .BR isnan ()
 152 (for all types) replacing them.
 153 Further note that the C99
 154 .BR isinf ()
 155 has weaker guarantees on the return value.
 156 See
 157 .BR fpclassify (3).
 158 .\"
 159 .\" finite* not on HP-UX; they exist on Tru64.
 160 .\" .SH HISTORY
 161 .\" The
 162 .\" .BR finite ()
 163 .\" function occurs in 4.3BSD.
 164 .\" see IEEE.3 in the 4.3BSD manual
 165 .SH SEE ALSO
 166 .BR fpclassify (3)