(const Value: string) vs (Value: string)

[[maeyanes]]

Aquí te pongo lo que dice la ayuda de Delphi sobre parámetros constantes:

Empezado por Delphi Help

A constant (const) parameter is like a local constant or read-only variable. Constant parameters are similar to value parameters, except that you can't assign a value to a constant parameter within the body of a procedure or function, nor can you pass one as a var parameter to another routine. (But when you pass an object reference as a constant parameter, you can still modify the object's properties.)

Using const allows the compiler to optimize code for structured- and string-type parameters. It also provides a safeguard against unintentionally passing a parameter by reference to another routine.

Here, for example, is the header for the CompareStr function in the SysUtils unit:

Código Delphi [-]
function CompareStr(const S1, S2: string): Integer;

Because S1 and S2 are not modified in the body of CompareStr, they can be declared as constant parameters.

Espero que te sirva para aclarar tu duda.


Saludos...



Update: Como siempre, Román se me adelantó...