man3/finite.3

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  25 .TH FINITE 3  2015-03-02 "" "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 .sp
  33 .BI "int finite(double " x );
  34 .br
  35 .BI "int finitef(float " x );
  36 .br
  37 .BI "int finitel(long double " x );
  38 .sp
  39 .BI "int isinf(double " x );
  40 .br
  41 .BI "int isinff(float " x );
  42 .br
  43 .BI "int isinfl(long double " x );
  44 .sp
  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 .sp
  52 .in -4n
  53 Feature Test Macro Requirements for glibc (see
  54 .BR feature_test_macros (7)):
  55 .in
  56 .sp
  57 .ad l
  58 .BR finite (),
  59 .BR finitef (),
  60 .BR finitel ():
  61 .RS 4
  62 _BSD_SOURCE || _SVID_SOURCE
  63 .RE
  64 .BR isinf ():
  65 .RS 4
  66 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE;
  67 .br
  68 or
  69 .I cc\ -std=c99
  70 .RE
  71 .br
  72 .BR isinff (),
  73 .BR isinfl ():
  74 .RS 4
  75 _BSD_SOURCE || _SVID_SOURCE
  76 .RE
  77 .BR isnan ():
  78 .RS 4
  79 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE;
  80 .br
  81 or
  82 .I cc\ -std=c99
  83 .RE
  84 .BR isnanf (),
  85 .BR isnanl ():
  86 .RS 4
  87 _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600
  88 .RE
  89 .ad b
  90 .SH DESCRIPTION
  91 The
  92 .BR finite (),
  93 .BR finitef (),
  94 and
  95 .BR finitel ()
  96 functions return a nonzero value if
  97 .I x
  98 is neither infinite
  99 nor a "not-a-number" (NaN) value, and 0 otherwise.
 100
 101 The
 102 .BR isnan (),
 103 .BR isnanf (),
 104 and
 105 .BR isnanl ()
 106 functions return a nonzero value if
 107 .I x
 108 is a NaN value,
 109 and 0 otherwise.
 110
 111 The
 112 .BR isinf (),
 113 .BR isinff (),
 114 and
 115 .BR isinfl ()
 116 functions return 1 if
 117 .I x
 118 is positive infinity, \-1 if
 119 .I x
 120 is negative infinity, and 0 otherwise.
 121 .SH ATTRIBUTES
 122 For an explanation of the terms used in this section, see
 123 .BR attributes (7).
 124 .TS
 125 allbox;
 126 lbw31 lb lb
 127 l l l.
 128 Interface       Attribute       Value
 129 T{
 130 .BR finite (),
 131 .BR finitef (),
 132 .BR finitel (),
 133 .br
 134 .BR isinf (),
 135 .BR isinff (),
 136 .BR isinfl (),
 137 .br
 138 .BR isnan (),
 139 .BR isnanf (),
 140 .BR isnanl ()
 141 T}      Thread safety   MT-Safe
 142 .TE
 143 .SH NOTES
 144 Note that these functions are obsolete.
 145 C99 defines macros
 146 .BR isfinite (),
 147 .BR isinf (),
 148 and
 149 .BR isnan ()
 150 (for all types) replacing them.
 151 Further note that the C99
 152 .BR isinf ()
 153 has weaker guarantees on the return value.
 154 See
 155 .BR fpclassify (3).
 156 .\"
 157 .\" finite* not on HP-UX; they exist on Tru64.
 158 .\" .SH HISTORY
 159 .\" The
 160 .\" .BR finite ()
 161 .\" function occurs in 4.3BSD.
 162 .\" see IEEE.3 in the 4.3BSD manual
 163 .SH SEE ALSO
 164 .BR fpclassify (3)