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NAME

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

SYNOPSIS

       #include <math.h>

       int finite(double x);
       int finitef(float x);
       int finitel(long double x);

       int isinf(double x);
       int isinff(float x);
       int isinfl(long double x);

       int isnan(double x);
       int isnanf(float x);
       int isnanl(long double x);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       finite(), finitef(), finitel(): _BSD_SOURCE || _SVID_SOURCE
       isinf(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
       _ISOC99_SOURCE; cc -std=c99
       isinff(), isinfl(): _BSD_SOURCE || _SVID_SOURCE
       isnan(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE ||
       _ISOC99_SOURCE; cc -std=c99
       isnanf(), isnanl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600

DESCRIPTION

       The  finite() functions return a nonzero value if x is neither infinite
       nor a "not-a-number" (NaN) value, and 0 otherwise.

       The isnan() functions return a nonzero value if x is a NaN value, and 0
       otherwise.

       The  isinf()  functions  return 1 if x is positive infinity, -1 if x is
       negative infinity, and 0 otherwise.

NOTES

       Note that these functions are obsolete.  C99 defines macros isfinite(),
       isinf(), and isnan() (for all types) replacing them.  Further note that
       the C99 isinf()  has  weaker  guarantees  on  the  return  value.   See
       fpclassify(3).

SEE ALSO

       fpclassify(3)

COLOPHON

       This  page  is  part of release 3.24 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

                                  2008-08-05