FPCLASSIFY (3) | C library functions | Unix Manual Pages | :man ▋

fpclassify, isfinite, isinf, isnan, isnormal - "classify a floating-point number"
CONTENTS
Library Synopsis Description See Also Standards History
LIBRARY
.Lb libm
SYNOPSIS
.In 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 .

isgreater (3), math (3), signbit (3)
STANDARDS
HISTORY