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Command: isnan | Section: 3 | Source: NetBSD | File: isnan.3
ISNAN(3) FreeBSD Library Functions Manual ISNAN(3)
NAME
isnan - test 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.
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").
CAVEATS
On VAX the isnan() function always returns 0, as the architecture doesn't
support NaN.
FreeBSD 14.1-RELEASE-p8 September 27, 2017 FreeBSD 14.1-RELEASE-p8