man3/finite.3

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  25 .TH FINITE 3  2017-09-15 "" "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 .BI "int finitef(float " x );
  35 .BI "int finitel(long double " x );
  36 .PP
  37 .BI "int isinf(double " x );
  38 .BI "int isinff(float " x );
  39 .BI "int isinfl(long double " x );
  40 .PP
  41 .BI "int isnan(double " x );
  42 .BI "int isnanf(float " x );
  43 .BI "int isnanl(long double " x );
  44 .fi
  45 .PP
  46 .in -4n
  47 Feature Test Macro Requirements for glibc (see
  48 .BR feature_test_macros (7)):
  49 .in
  50 .PP
  51 .ad l
  52 .BR finite (),
  53 .BR finitef (),
  54 .BR finitel ():
  55 .RS 4
  56 /* Glibc since 2.19: */ _DEFAULT_SOURCE
  57     || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  58 .RE
  59 .BR isinf ():
  60 .RS 4
  61 _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE
  62     || /* Glibc since 2.19: */ _DEFAULT_SOURCE
  63     || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  64 .RE
  65 .br
  66 .BR isinff (),
  67 .BR isinfl ():
  68 .RS 4
  69 /* Glibc since 2.19: */ _DEFAULT_SOURCE
  70     || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  71 .RE
  72 .BR isnan ():
  73 .RS 4
  74 _XOPEN_SOURCE || _ISOC99_SOURCE
  75     || /* Glibc since 2.19: */ _DEFAULT_SOURCE
  76     || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  77 .RE
  78 .BR isnanf (),
  79 .BR isnanl ():
  80 .RS 4
  81 _XOPEN_SOURCE\ >=\ 600
  82     || /* Glibc since 2.19: */ _DEFAULT_SOURCE
  83     || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
  84 .RE
  85 .ad b
  86 .SH DESCRIPTION
  87 The
  88 .BR finite (),
  89 .BR finitef (),
  90 and
  91 .BR finitel ()
  92 functions return a nonzero value if
  93 .I x
  94 is neither infinite
  95 nor a "not-a-number" (NaN) value, and 0 otherwise.
  96 .PP
  97 The
  98 .BR isnan (),
  99 .BR isnanf (),
 100 and
 101 .BR isnanl ()
 102 functions return a nonzero value if
 103 .I x
 104 is a NaN value,
 105 and 0 otherwise.
 106 .PP
 107 The
 108 .BR isinf (),
 109 .BR isinff (),
 110 and
 111 .BR isinfl ()
 112 functions return 1 if
 113 .I x
 114 is positive infinity, \-1 if
 115 .I x
 116 is negative infinity, and 0 otherwise.
 117 .SH ATTRIBUTES
 118 For an explanation of the terms used in this section, see
 119 .BR attributes (7).
 120 .TS
 121 allbox;
 122 lbw31 lb lb
 123 l l l.
 124 Interface       Attribute       Value
 125 T{
 126 .BR finite (),
 127 .BR finitef (),
 128 .BR finitel (),
 129 .br
 130 .BR isinf (),
 131 .BR isinff (),
 132 .BR isinfl (),
 133 .br
 134 .BR isnan (),
 135 .BR isnanf (),
 136 .BR isnanl ()
 137 T}      Thread safety   MT-Safe
 138 .TE
 139 .SH NOTES
 140 Note that these functions are obsolete.
 141 C99 defines macros
 142 .BR isfinite (),
 143 .BR isinf (),
 144 and
 145 .BR isnan ()
 146 (for all types) replacing them.
 147 Further note that the C99
 148 .BR isinf ()
 149 has weaker guarantees on the return value.
 150 See
 151 .BR fpclassify (3).
 152 .\"
 153 .\" finite* not on HP-UX; they exist on Tru64.
 154 .\" .SH HISTORY
 155 .\" The
 156 .\" .BR finite ()
 157 .\" function occurs in 4.3BSD.
 158 .\" see IEEE.3 in the 4.3BSD manual
 159 .SH SEE ALSO
 160 .BR fpclassify (3)