PARAMETERS

    PARAMETERS identifies memory variables that receive passed values or
    references.

Syntax

    PARAMETERS <parameter list>

Argument

    <memvar list> is one or more receiving memory variables separated by
    commas.  The number of receiving variables does not have to match the
    number of parameters passed.

Usage

    Parameters are defined as either format or actual.  Formal parameters
    are the receiving memory variables specified as arguments of the
    PARAMETERS statement.  Actual parameters are the arguments of the
    calling DO...WITH or user-defined function.

    There are two methods of passing parameters, by value or by reference.
    By value means that the actual parameter is evaluated and the result is
    placed in a memory location.  When the subsequent PARAMETERS executes,
    the value is transferred to the receiving variable.  Passing by
    reference, by contrast, means that a pointer to the location of the
    actual parameter is passed instead of the value.  Subsequent changes to
    the formal parameter are actually changes to the actual parameter,
    hence the term passing by reference.

    Note that in Clipper there is no argument checking and therefore no
    requirement that the number of actual parameters match the number of
    formal parameters.  To determine the number of actual parameters passed
    use PCOUNT().

    Passing parameters to procedures and user-defined functions: The
    following rules apply when you pass memory variables and arrays to
    procedures and user-defined functions:

    1.  Memory variables and array identifiers are passed by reference to
        procedures.  Array elements, expressions, variables within
        parentheses, and fields are passed by value (fields must be bounded
        by parentheses).

    2.  Parameters are passed by value to functions by default; however,
        they can be passed by reference if the variable is preceded by the
        "at" sign (@).  Arrays are always passed by reference; array
        elements can only be passed by value.

    Passing parameters from the DOS command line: You can pass multiple
    character strings to your program from the DOS command line.  The
    character strings must be separated by spaces.  A parameter bounded by
    quotes is passed as one string.  For example:

    C>PROG "CLIPPER COMPILER" 5

    The routine that receives parameters from the DOS command should test
    the number of passed parameters with PCOUNT() to assure that critical
    parameters are defined.