Shachar Shemesh <[EMAIL PROTECTED]> writes: > There is no difference between the first a() and the second > a(). Both are temporary variables of type a generated by an empty > constructor.
Yes, there is a difference, and I suspect that is what you are missing. In the first case you create a temp a() and call its method. In the second case the compiler generates a temporary variable to hold your a() and passes a reference to that temp to func2. However, the compiler is only willing to generate a const temp because it would be silly to modify a temp and immediately destroy it. The equivalent code for your second line is const a temp = a(); a::func2(temp); The temp is necessary because you want to pass a reference to func2. A reference can only be initialized with an lvalue (an object whose address you can take). Your a() is not an lvalue (you cannot say a() = something), but that's OK: you can initialize a const reference: * convert the type to a if necessary (you don't need this in your example) * place the result into a temp of type a * use the temp as initializer But - again! - this is only allowed for consts because otherwise you'd be in a highly error-prone situation: you would think you are modifying a variable, but instead you would be modifying a temp. -- Oleg Goldshmidt | [EMAIL PROTECTED] | http://www.goldshmidt.org ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
