NAME
fpclassify —
classify real floating
type
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <math.h>
int
fpclassify(
real-floating
x);
DESCRIPTION
The
fpclassify() macro performs classification of its argument
x. An argument represented in a format wider than its
semantic type is converted to its semantic type first. The classification is
then based on the type of the argument.
IEEE 754
FP_INFINITE
- infinity, either positive or negative
FP_NAN
- not-a-number (“NaN”)
FP_NORMAL
- normal
FP_SUBNORMAL
- subnormal
FP_ZERO
- zero
VAX
FP_ROP
- reserved operand (“ROP”)
FP_DIRTYZERO
- dirty zero
FP_NORMAL
- finite
FP_ZERO
- true zero
RETURN VALUES
The
fpclassify() macro returns the value of the number
classification macro appropriate to its argument
x as
described above.
ERRORS
No errors are defined.
SEE ALSO
isfinite(3),
isnormal(3),
math(3),
signbit(3)
STANDARDS
The
fpclassify() macro conforms to
ISO/IEC
9899:1999 (“ISO C99”).