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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;
           or cc -std=c99
       isinff(), isinfl():
           _BSD_SOURCE || _SVID_SOURCE
       isnan():
           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE;
           or 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 3.35 of the Linux man-pages project.  A  description  of  the
       project,  and information about reporting bugs, can be found at http://man7.org/linux/man-
       pages/.

                                            2008-08-05                                  FINITE(3)