1FINITE(3)                  Linux Programmer's Manual                 FINITE(3)
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NAME

6       finite,  finitef, finitel, isinf, isinff, isinfl, isnan, isnanf, isnanl
7       - BSD floating-point classification functions
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SYNOPSIS

10       #include <math.h>
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12       int finite(double x);
13       int finitef(float x);
14       int finitel(long double x);
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16       int isinf(double x);
17       int isinff(float x);
18       int isinfl(long double x);
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20       int isnan(double x);
21       int isnanf(float x);
22       int isnanl(long double x);
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24   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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26       finite(), finitef(), finitel():
27           /* Glibc since 2.19: */ _DEFAULT_SOURCE
28               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
29       isinf():
30           _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE
31               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
32               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
33       isinff(), isinfl():
34           /* Glibc since 2.19: */ _DEFAULT_SOURCE
35               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
36       isnan():
37           _XOPEN_SOURCE || _ISOC99_SOURCE
38               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
39               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
40       isnanf(), isnanl():
41           _XOPEN_SOURCE >= 600
42               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
43               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

46       The finite(), finitef(), and finitel() functions return a nonzero value
47       if x is neither infinite nor a "not-a-number" (NaN) value, and 0 other‐
48       wise.
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50       The isnan(), isnanf(), and isnanl() functions return a nonzero value if
51       x is a NaN value, and 0 otherwise.
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53       The isinf(), isinff(), and isinfl() functions return 1 if x is positive
54       infinity, -1 if x is negative infinity, and 0 otherwise.
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ATTRIBUTES

57       For  an  explanation  of  the  terms  used   in   this   section,   see
58       attributes(7).
59
60       ┌────────────────────────────────┬───────────────┬─────────┐
61       │Interface                       │ Attribute     │ Value   │
62       ├────────────────────────────────┼───────────────┼─────────┤
63       │finite(), finitef(), finitel(), │ Thread safety │ MT-Safe │
64       │isinf(), isinff(), isinfl(),    │               │         │
65       │isnan(), isnanf(), isnanl()     │               │         │
66       └────────────────────────────────┴───────────────┴─────────┘

NOTES

68       Note that these functions are obsolete.  C99 defines macros isfinite(),
69       isinf(), and isnan() (for all types) replacing them.  Further note that
70       the C99 isinf() has weaker guarantees on the return value.  See fpclas‐
71       sify(3).
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SEE ALSO

74       fpclassify(3)
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COLOPHON

77       This page is part of release 4.16 of the Linux  man-pages  project.   A
78       description  of  the project, information about reporting bugs, and the
79       latest    version    of    this    page,    can     be     found     at
80       https://www.kernel.org/doc/man-pages/.
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84                                  2017-09-15                         FINITE(3)