IEEE_CLASS(3I) Last changed: 1-6-98
NAMEIEEE_CLASS - Returns the class to which x belongs
SYNOPSISIEEE_CLASS ([X=]x)
IMPLEMENTATION
UNICOS/mk and IRIX systems
CRAY T90 systems that support IEEE floating-point arithmetic
STANDARDS
CF90 and MIPSpro 7 Fortran 90 compiler extension to Fortran 90
IEEE Standard for Binary Floating-point Arithmetic
DESCRIPTION
A floating-point number can be classified several ways, such as a
quiet NaN, a signaling NaN, -0, +inf, etc. The IEEE_CLASS intrinsic
function returns a value that indicates the class to which x belongs.
This function accepts the following argument:
x Must be of type real.
IEEE_CLASS is an elemental function. The name of this intrinsic
cannot be passed as an argument.
NOTES
The IEEE intrinsic procedures use the named constants contained in a
system module, so you must include one of the following statements in
your program:
* On UNICOS and UNICOS/mk systems: USE CRI_IEEE_DEFINITIONS
* On UNICOS, UNICOS/mk, and IRIX systems: USE FTN_IEEE_DEFINITIONS
The CRI_IEEE_DEFINITIONS module is obsolescent. It will be removed
for the CF90 4.0 release.
RETURN VALUES
The result type and type parameter is default integer. If x is an
array, the result is an array of the same shape as x.
The value returned has a value represented by one of the following
named constants:
IEEE_CLASS_SIGNALING_NAN
IEEE_CLASS_QUIET_NAN
IEEE_CLASS_NEG_INFINITY
IEEE_CLASS_NEG_NORM_NONZERO
IEEE_CLASS_NEG_DENORM
IEEE_CLASS_NEG_ZERO
IEEE_CLASS_POS_ZERO
IEEE_CLASS_POS_DENORM
IEEE_CLASS_POS_NORM_NONZERO
IEEE_CLASS_POS_INFINITY
EXAMPLES
REAL x
... ! Compute X.
SELECT CASE (IEEE_CLASS(x))
CASE IEEE_CLASS_SIGNALING_NAN
... ! Do something.
CASE IEEE_CLASS_QUIET_NAN
... ! Do something else.
... ! Other cases.
END SELECT
SEE ALSO
Intrinsic Procedures Reference Manual, publication SR-2138, for the
printed version of this man page.
