NAME    [Toc]    [Back]

     fpclassify, isfinite, isinf, isnan, isnormal -- classify a floating-point
     number

LIBRARY    [Toc]    [Back]

     Standard C Library (libc, -lc)

SYNOPSIS    [Toc]    [Back]

     #include <math.h>

     int
     fpclassify(real-floating x);

     int
     isfinite(real-floating x);

     int
     isinf(real-floating x);

     int
     isnan(real-floating x);

     int
     isnormal(real-floating x);

DESCRIPTION    [Toc]    [Back]

     The fpclassify() macro takes an argument of x and returns one of the following
 manifest constants.

     FP_INFINITE   Indicates that x is an infinite number.

     FP_NAN	   Indicates that x is not a number (NaN).

     FP_NORMAL	   Indicates that x is a normalized number.

     FP_SUBNORMAL  Indicates that x is a denormalized number.

     FP_ZERO	   Indicates that x is zero (0 or -0).

     The isfinite() macro returns a non-zero value if and only if its argument
     has a finite (zero, subnormal, or normal) value.  The isinf(), isnan(),
     and isnormal() macros return non-zero if and only if x is an infinity,
     NaN, or a non-zero normalized number, respectively.

     The symbol isnanf() is provided as an alias to isnan() for compatibility,
     and its use is deprecated.

SEE ALSO    [Toc]    [Back]

     isgreater(3), math(3), signbit(3)

STANDARDS    [Toc]    [Back]

     The fpclassify(), isfinite(), isinf(), isnan(), and isnormal() macros
     conform to ISO/IEC 9899:1999 (``ISO C99'').

HISTORY    [Toc]    [Back]

     The fpclassify(), isfinite(), isinf(), isnan(), and isnormal() macros
     were added in FreeBSD 5.1.  3BSD introduced isinf() and isnan() functions,
 which accepted double arguments; these have been superseded by the
     macros described above.

BUGS    [Toc]    [Back]

     By default, the DEC Alpha architecture does not support IEEE rounding.
     See the compiler documentation for additional details.


FreeBSD 5.2.1		       February 12, 2003		 FreeBSD 5.2.1