# isnan(3) [netbsd man page]

ISNAN(3) BSD Library Functions Manual ISNAN(3)NAME

isnantest for not-a-number--LIBRARY

Standard C Library (libc, -lc)SYNOPSIS

#include <math.h> int isnan(real-floating x);DESCRIPTION

The isnan() macro determines whether its argument x is not-a-number (``NaN''). An argument represented in a format wider than its semantic type is converted to its semantic type first. The determination is then based on the type of the argument. IEEE 754 It is determined whether the value of x is a NaN. VAX NaNs are not supported.RETURN VALUES

The isnan() macro returns a non-zero value if the value of x is a NaN. Otherwise 0 is returned.SEE ALSO

fpclassify(3), isfinite(3), isinf(3), isinff(3), isnanf(3), isnormal(3), math(3), signbit(3) IEEE Standard for Binary Floating-Point Arithmetic, Std 754-1985, ANSI.STANDARDS

The isnan() macro conforms to ISO/IEC 9899:1999 (``ISO C99'').BSD

March 5, 2004 BSD

## Check Out this Related Man Page

FPCLASSIFY(3) BSD Library Functions Manual FPCLASSIFY(3)NAME

fpclassify, isfinite, isinf, isnan, isnormalclassify 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added in FreeBSD 5.1. 3BSD introduced isinf() and isnan() func- tions, which accepted double arguments; these have been superseded by the macros described above.BSD

January 26, 2005 BSD