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ISINF(3)                    BSD Programmer's Manual                   ISINF(3)

NAME
     isinf, isnan - test for infinity or not-a-number

SYNOPSIS
     int
     isinf(double);

     int
     isnan(double);

DESCRIPTION
     The isninf() function returns 1 if the number is ``infinity'', otherwise
     0.

     The isnan() function returns 1 if the number is ``not-a-number'', other-
     wise 0.

SEE ALSO
     math(3)

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

BUGS
     Neither the VAX nor the Tahoe floating point have distinguished values
     for either infinity or not-a-number.  These routines always return 0 on
     those architectures.

4.4BSD                         January 29, 1994                              1