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           _BSD_SOURCE || _SVID_SOURCE
28       isinf():
29           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
30           _ISOC99_SOURCE;
31           or cc -std=c99
32       isinff(), isinfl():
33           _BSD_SOURCE || _SVID_SOURCE
34       isnan():
35           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE;
36           or cc -std=c99
37       isnanf(), isnanl():
38           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600
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DESCRIPTION

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

52   Multithreading (see pthreads(7))
53       The   finite(),  finitef(),  finitel(),  isinf(),  isinff(),  isinfl(),
54       isnan(), isnanf(), and isnanl() functions are thread-safe.
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NOTES

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

63       fpclassify(3)
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COLOPHON

66       This  page  is  part of release 3.53 of the Linux man-pages project.  A
67       description of the project, and information about reporting  bugs,  can
68       be found at http://www.kernel.org/doc/man-pages/.
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72                                  2013-07-22                         FINITE(3)