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 <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 3.25 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                                                  FINITE(3)