DragonFly On-Line Manual Pages


FPCLASSIFY(3)	      DragonFly 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. The symbol isnanf() is provided as an alias to isnan() for compatibility, and its use is deprecated. Similarly, finite() and finitef() are depre- cated 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in DragonFly 1.3. 3BSD introduced isinf() and isnan() func- tions, which accepted double arguments; these have been superseded by the macros described above. DragonFly 4.1 January 26, 2005 DragonFly 4.1