Combining const and out parameters
This is a continuation of a previous blog post, Are const parameters dangerous? Basically, adding an out parameter into the mix does not change anything that has been said in the previous post about using const parameters. But out parameters, with their own side-effects, create a specific situation that requires additional explanation. First, let's see how an out parameter works. An out parameter is a var parameter with a twist. Just like a var parameter passes the original variable as a reference (pointer), so does the out parameter, but out also tells the compiler that the original value can be discarded, since it is not for passing any input data to the procedure, and will be only used for passing the result out of the procedure. For managed types, the compiler will clear the original contents of the out parameter at the call site. procedure OutInt(out p: integer); begin p := 5; end; procedure OutString(out p: string); begin p := '5'; end; procedure T...
