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MEMVAR
Declare private and public variable names
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Syntax
MEMVAR <idMemvar list>
Arguments
<idMemvar list> is a list of public and private variable names to
declare to the compiler.
Description
MEMVAR is a declaration statement that causes the compiler to resolve
references to variables specified without an explicit alias by
implicitly assuming the memory variable alias (MEMVAR->). Only
explicit, unaliased references to the specified variables are affected.
MEMVAR, like all declaration statements, has no effect on references
made within macro expressions or variables.
The MEMVAR statement neither creates the variables nor verifies their
existence. Its primary effect is to ensure correct references to
variables whose existence is known to be guaranteed at runtime. At
runtime, the specified variables must be created using the PRIVATE,
PARAMETERS or PUBLIC statements. This can occur in the procedure
containing the MEMVAR declaration or in a higher -level procedure.
Attempting to access the variables before they are created will cause an
error.
The scope of the MEMVAR declaration is the procedure or function in
which it occurs, or the entire source file if it precedes any PROCEDURE
or FUNCTION statements and the /N compiler option is used. The /N
option suppresses automatic definition of a procedure with the same name
as the program (.prg) file.
Like other declaration statements, MEMVAR must precede any executable
statements, including PARAMETERS, PUBLIC, and PRIVATE statements in a
procedure or function definition, or the program (.prg) file if the
declaration has filewide scope.
MEMVAR can be used in conjunction with the /W compiler option--which
generates warning messages for ambiguous variable references--to perform
compile--time checking for undeclared variables.
For more information on variable declarations and scoping, refer to the
Variables section in the "Basic Concepts" chapter of the Programming and
Utilities Guide.
Examples
. This example demonstrates the relationship between a private
and field variable with the same name. The private variable is
declared with the MEMVAR statement:
FUNCTION Example
MEMVAR amount, address
PRIVATE amount := 100
USE Customer NEW
//
? amount // Refers to amount private variable
? Customer->Amount // Refers to Amount field variable
//
RETURN NIL
See Also: FIELD LOCAL PRIVATE PUBLIC STATIC
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