NAME    [Toc]    [Back]

     isinf, isinff, isnan, isnanf - test for infinity  or  not-anumber

SYNOPSIS    [Toc]    [Back]

     #include <math.h>

     int
     isinf(double n);

     int
     isinff(float n);

     int
     isnan(double n);

     int
     isnanf(float n);

DESCRIPTION    [Toc]    [Back]

     The  isinf() function returns 1 if the number n is Infinity,
otherwise 0.
     The isinff() function  is  a  single  precision  version  of
isinf().

     The  isnan()  function returns 1 if the number n is ``not-anumber'', otherwise
 0.  The isnanf() function is a single precision  version of
     isnan().

SEE ALSO    [Toc]    [Back]

     math(3)

     IEEE  Standard  for  Binary  Floating-Point  Arithmetic, Std
754-1985, ANSI.

BUGS    [Toc]    [Back]

     VAX floating point does not have  distinguished  values  for
either infinity
     or not-a-number.  These routines always return 0 on that architecture.

OpenBSD     3.6                        January      29,      1994