FPCLASSIFY(3)          FreeBSD 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
     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.  Similarly, finite() and finitef() are
     deprecated versions of isfinite().

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
     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     functions, which accepted double arguments; these have been superseded by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.

FreeBSD 13.1-RELEASE-p6        January 26, 2005        FreeBSD 13.1-RELEASE-p6