Delphi Language Guide Delphi for Microsoft Win32 Delphi for the Microsoft. Net framework

Default Parameters and Overloaded Functions
If you use default parameter values in an overloaded routine, avoid ambiguous parameter signatures. Consider, for
example, the following.
procedure Confused(I: Integer); overload;
   ...
procedure Confused(I: Integer; J: Integer = 0); overload;
   ...
Confused(X);   //  Which procedure is called?
In fact, neither procedure is called. This code generates a compilation error.
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Default Parameters in Forward and Interface Declarations
If a routine has a forward declaration or appears in the interface section of a unit, default parameter valuesif there
are anymust be specified in the forward or interface declaration. In this case, the default values can be omitted from
the defining (implementation) declaration; but if the defining declaration includes default values, they must match
those in the forward or interface declaration exactly.
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