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fpclassify(3M)

HP-UX 11i Version 3: February 2007
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NAME

fpclassify() — floating-point value classification macro

SYNOPSIS

#include <math.h>

int fpclassify( floating-type x);

DESCRIPTION

The fpclassify() macro classifies its argument value as NaN, infinite, normalized, denormalized, or zero. The argument must be of floating type, and classification is based on the type of the argument. For HP Integrity servers, the argument can be any floating type. For PA-RISC, the argument must be either double or float.

The fpclassify() macro, used in conjunction with the signbit() macro, replaces the fpclassify() and fpclassifyf() functions, which are obsolete and are no longer supported.

USAGE

To use the fpclassify() macro, compile either with the default -Ae option or with the -Aa and -D_HPUX_SOURCE options. Make sure your program includes <math.h>. Link in the math library by specifying -lm on the compiler or linker command line.

RETURN VALUE

The fpclassify() macro returns the value of the number classification macro appropriate to the type and value of its argument.

The value returned is one of the following macros, which are defined in <math.h>:

FP_NORMAL Normalized FP_ZERO Zero FP_INFINITE Infinity FP_SUBNORMAL Denormalized FP_NAN NaN

Every possible argument value falls into one of these categories, so this macro never results in an error.

The macro raises no exceptions.

ERRORS

No errors are defined.

EXAMPLES

Take certain actions if x is either a denormalized float value or zero:

#include <math.h> /*...*/ int class; float x; /*...*/ class = fpclassify(x); if ( (class == FP_SUBNORMAL) || (class == FP_ZERO) ) { /*...*/ }

STANDARDS CONFORMANCE

fpclassify(): ISO/IEC C99

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