Open Watcom FORTRAN 77 Language Reference

Language Reference
Example:
* Illegal order of statement functions.
.
.
.
F(X) = X + G(X)
G(X) = X + 2
.
.
.
3. The statement function name must not be the same name of any other entity in the program unit
except possibly the name of a common block.
4. If a dummy argument of a statement function is of type CHARACTER, then its length
specification must be an integer constant expression. The following is illegal.
Example:
SUBROUTINE SAM( X )
CHARACTER*(*) X
* Illegal - CHARACTER*(*) dummy argument not
* allowed in statement function.
F(X) = X
PRINT *, F(’ABC’)
END
5. An actual argument to a statement function can be any expression, except character expressions
involving the concatenation of an operand whose length specification is (*) unless the operand
is a symbolic constant.
12.3 Intrinsic Functions
An intrinsic function is a function that is provided by Open Watcom FORTRAN 77.
12.3.1 Specific Names and Generic Names of Intrinsic Functions
All intrinsic functions can be referenced by using the generic name or the specific name of the intrinsic
function. The specific name uniquely identifies the function to be performed. The type of the result is
predefined thus its name need not appear in a type statement. For example, CLOG is a specific name of the
generic LOG function and computes the natural logarithm of a complex number. The type of the result is
also COMPLEX.
When the generic name is used, a specific name is selected based on the data type of the actual argument.
For example, the generic name of the natural logarithm intrinsic function is LOG. To compute the natural
logarithm of REAL, DOUBLE PRECISION, COMPLEX or DOUBLE PRECISION COMPLEX data, the
generic name LOG can be used. Generic names simplify the use of intrinsic functions because the same
name can be used with more than one type of argument.
246 Intrinsic Functions