Core Function IsDeclared

IsDeclared( <variable name> )

Description

Check if a variable has been declared

Parameters

Expression

String representing name of the variable to be checked.

Return Value

Success: Returns 1 if variable has been assigned.

Failure: Returns 0 if variable doesn't exist yet.

Remarks

Example

If (!IsDeclared("a"))
    MsgBox('$a is NOT declared');     // $a has never been assigned
 
$a=1;
 
If (IsDeclared ("a"))
    MsgBox('$a IS declared');      //due to previous $a=1 assignment