If the prototyped call interface involves the passing of parameters then
you must define the parameter immediately following the PR or PI specification.
The following keywords, which apply to defining the type, are allowed on the
parameter definition specifications:
ASCEND
The array is in ascending sequence.
DATFMT(fmt)
The date parameter has the format fmt.
DESCEND
The array is in descending sequence.
DIM(N)
The parameter is an array or data structure with
N elements.
LIKE(name)
The parameter is defined like the item specified by the keyword.
LIKEREC(name{,type})
The parameter is a data structure whose subfields are the same as the
fields in the specified record format name.
LIKEDS(data_structure_name)
The parameter is a data structure whose subfields are the same as the
subfields identified in the LIKEDS keyword.
LIKEFILE(filename)
The parameter is a file, either filename or
a file related through the LIKEFILE keyword to filename.
PROCPTR
The parameter is a procedure pointer.
TIMFMT(fmt)
The time parameter has the format fmt.
VARYING{(2|4)}
A character, graphic, or UCS-2 parameter has a variable-length format.
The following keywords, which specify how the parameter should be passed,
are also allowed on the parameter definition specifications:
CONST
The parameter is passed by read-only reference. A parameter defined
with CONST must not be modified by the called program or procedure. This parameter-passing
method allows you to pass literals and expressions.
NOOPT
The parameter will not be optimized in the called program or procedure.
Where opt1 ... opt5 can be *NOPASS, *OMIT, *VARSIZE, *STRING, *TRIM,
or *RIGHTADJ. For example, OPTIONS(*VARSIZE : *NOPASS).
Specifies the following parameter passing options:
*NOPASS
The parameter does not have to be passed. If a parameter has OPTIONS(*NOPASS)
specified, then all parameters following it must also have OPTIONS(*NOPASS)
specified.
*OMIT
The special value *OMIT may be passed for this reference parameter.
*VARSIZE
The parameter may contain less data than is indicated on the definition.
This keyword is valid only for character parameters, graphic parameters, UCS-2
parameters, or arrays passed by reference. The called program or procedure
must have some way of determining the length of the passed parameter.
Note:
When this keyword is omitted for fixed-length fields, the parameter
may only contain more or the same amount of data as indicated on the definition;
for variable-length fields, the parameter must have the same declared maximum
length as indicated on the definition.
*STRING
Pass a character value as a null-terminated string. This keyword is
valid only for basing pointer parameters passed by value or by read-only reference.
*TRIM
The parameter is trimmed before it is passed. This option is valid
for character, UCS-2 or graphic parameters passed by value or by read-only
reference. It is also valid for pointer parameters that have OPTIONS(*STRING)
coded.
Note:
When a pointer parameter has OPTIONS(*STRING : *TRIM)
specified, the value will be trimmed even if a pointer is passed directly.
The null-terminated string that the pointer is pointing to will be copied
into a temporary, trimmed of blanks, with a new null-terminator added at the
end, and the address of that temporary will be passed.
*RIGHTADJ
For a CONST or VALUE parameter, *RIGHTADJ indicates that the graphic,
UCS-2, or character parameter value is to be right adjusted.
TIP
For the parameter passing options *NOPASS, *OMIT, and *VARSIZE, it is up
to the programmer of the procedure to ensure that these options are handled.
For example, if OPTIONS(*NOPASS) is coded and you choose not to pass the parameter, the procedure must check that the parameter
was passed before it accesses it. The compiler will not do any checking for
this.
VALUE
The parameter is passed by value.
For information on the keywords listed above, see Definition-Specification Keywords.
For more information on using prototyped parameters, see the chapter on calling
programs and procedures in the IBM Rational Development Studio for i: ILE RPG Programmer's Guide.