PARAMETERS

PARAMETERS

Declares private parameter variables

Syntax

PARAMETERS <idPrivate list>

Arguments

<idPrivate list> is one or more parameter variables separated by commas.

The number of receiving variables does not have to match the number of arguments passed by the calling procedure or user-defined function.

Description

The PARAMETERS statement declares private variables to receive passed values or references. Receiving variables are referred to as parameters. The values or references actually passed by a procedure or user-defined function invocation are referred to as arguments.

When a PARAMETERS statement executes, all variables in the parameter list are created as private variables and all public or private variables with the same names are hidden until the current procedure or user-defined function terminates. A PARAMETERS statement is an executable statement and, therefore, can occur anywhere in a procedure or user-defined function, but must follow all compile-time variable declarations, such as FIELD, LOCAL, MEMVAR, and STATIC.

Parameters can also be declared as local variables if specified as a part of the PROCEDURE or FUNCTION declaration statement (see the example). Parameters specified in this way are referred to as formal parameters. Note that you cannot specify both formal parameters and a PARAMETERS statement with a procedure or user-defined function definition. Attempting to do this results in a fatal compiler error and an object file is not generated.

In Harbour the number of arguments and parameters do not have to match. If you specify more arguments than parameters, the extra arguments are ignored. If you specify fewer arguments than parameters, the extra parameters are created with a NIL value. If you skip an argument, the corresponding parameter is initialized to NIL. The PCOUNT() function returns the position of the last argument passed in the list of arguments. This is different from the number of parameters passed since it includes skipped parameters.

Examples

     .  This user-defined function receives values passed into private
        parameters with a PARAMETERS statement:

        FUNCTION MyFunc
           PARAMETERS cOne, cTwo, cThree
           ? cOne, cTwo, cThree
           RETURN NIL

     .  This example is similar, but receives values passed into local
        variables by declaring the parameter variables within the FUNCTION
        declaration:

        FUNCTION MyFunc( cOne, cTwo, cThree )
           ? cOne, cTwo, cThree
           RETURN NIL

See Also

 FUNCTION, LOCAL, PCOUNT(), PRIVATE, PROCEDURE, STATIC

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One response to “PARAMETERS

  1. Pingback: Harbour Statements | Viva Clipper !

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