fpclassify , isfinite , isinf , isnan , isnormal
- classify a floating-point number
LIBRARY
Lb libm
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
Fa x
and returns one of the following manifest constants.
FP_INFINITE
Indicates that
Fa x
is an infinite number.
FP_NAN
Indicates that
Fa x
is not a number (NaN).
FP_NORMAL
Indicates that
Fa x
is a normalized number.
FP_SUBNORMAL
Indicates that
Fa x
is a denormalized number.
FP_ZERO
Indicates that
Fa 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
Fa 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 (.);
The
fpclassify (,);
isfinite (,);
isinf (,);
isnan (,);
and
isnormal ();
macros conform to
St -isoC-99 .
HISTORY
The
fpclassify (,);
isfinite (,);
isinf (,);
isnan (,);
and
isnormal ();
macros were added in
Fx 5.1 .
BSD 3
introduced
isinf ();
and
isnan ();
functions, which accepted
Vt double
arguments; these have been superseded by the macros
described above.
