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fpclassify(3)            BSD Library Functions Manual            fpclassify(3)


NAME

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


LIBRARY

     Math Library (libm, -lm)


SYNOPSIS

     #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

     The fpclassify() macro takes an argument of x and returns one of the fol-
     lowing 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.


SEE ALSO

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


STANDARDS

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


HISTORY

     3BSD introduced isinf() and isnan() functions, which accepted double
     arguments; these have been superseded by the macros described above.

BSD                            December 11, 2006                           BSD

Mac OS X 10.6 - Generated Thu Sep 17 20:19:51 CDT 2009
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