Prototyped Parameters

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.

For information on these keywords, see Definition-Specification Keywords.

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.

OPTIONS(option1 { : option2 { : option3 { … } } }) : Where the options can be *NOPASS, *OMIT, *VARSIZE, *STRING, *TRIM, *RIGHTADJ, *NULLIND, *EXACT, or *CONVERT. 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.
    See [OPTIONS(\*NOPASS)](/doc/en/docs/rpg-reference/doptns/#doptns__nopass).

\*OMIT
:   The special value \*OMIT may be passed for this reference parameter.
    See [OPTIONS(\*OMIT)](/doc/en/docs/rpg-reference/doptns/#doptns__omit)

\*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.

    See [OPTIONS(\*VARSIZE)](/doc/en/docs/rpg-reference/doptns/#doptns__varsize)

\*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.
    See [OPTIONS(\*STRING)](/doc/en/docs/rpg-reference/doptns/#doptns__string)

\*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) or OPTIONS(\*CONVERT : \*TRIM) specified, the value is trimmed
    even if a pointer is passed directly. The null-terminated string that
    the pointer is pointing to is copied into a temporary, trimmed
    of blanks, with a new null-terminator added at the end, and the address
    of that temporary is passed.

    See [OPTIONS(\*TRIM)](/doc/en/docs/rpg-reference/doptns/#doptns__trim)

\*RIGHTADJ
:   For a CONST or VALUE parameter, \*RIGHTADJ indicates that the
    graphic, UCS-2, or character parameter value is to be right adjusted.
    See [OPTIONS(\*RIGHTADJ)](/doc/en/docs/rpg-reference/doptns/#doptns__rightadj)

\*NULLIND
:   When OPTIONS(\*NULLIND) is specified for a parameter, the null-byte
    map is passed with the parameter, giving the called procedure direct access
    to the null-byte map of the caller's parameter.
    See [OPTIONS(\*NULLIND)](/doc/en/docs/rpg-reference/doptns/#doptns__nullind).

\*EXACT
:   When OPTIONS(\*EXACT) is specified, the compiler is more strict about the parameters
    that may be passed.
    See [OPTIONS(\*EXACT)](/doc/en/docs/rpg-reference/doptns/#doptns__exact).

\*CONVERT
:   When OPTIONS(\*CONVERT) is specified for a parameter,
    the data type of the passed parameter can be different from the
    data type of the prototyped parameter.
    See [OPTIONS(\*CONVERT)](/doc/en/docs/rpg-reference/doptns/#doptns__convert).

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 Rational® Development Studio for i: ILE RPG Programmer’s Guide.