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



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

SYNOPSIS
       #include <&lt;math.h>&gt;

       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(), isinff(), isinfl(): _BSD_SOURCE || _SVID_SOURCE
       isnan(), isnanf(), isnanl(): _BSD_SOURCE || _SVID_SOURCE ||
       _XOPEN_SOURCE

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

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

       The  isinf()  functions  return 1 if x is positive infinity, -1 is 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 fpclas-
       sify(3).

SEE ALSO
       fpclassify(3)

COLOPHON
       This  page  is  part of release 3.05 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/.



                                  2007-07-26                         FINITE(3)