On Mon, Mar 27, 2006 at 05:47:35PM +0200, Olaf van der Spek wrote:
On 3/27/06, Pavol Droba <droba@topmail.sk> wrote:
Thanks, that did the trick. I understand T -> T& isn't valid (although I don't like that), but why doesn't it automatically do T -> const T&?
Sorry, somehow I thought, that it is solved. The main reason why it works this way is the template instantiation process. const T& is more specific type then T& and so if T& matches the template signature, it is used.
But in this case it can't be used.
As I mentioned in another post, this behaviour is implemented in the library intentionaly, since it disallows to pass temporary objects as the arguments on the certain places.
I understand, but isn't it possible to have both advantages? For example, by adding a function that takes const T&?
This is an option, but there are several problem. First there are some older compilers, that do not support partial template ordering. Also it would multiply number of functions 2 times. I'm not sure if it is worth it.
Or should all functions (in all applications and libraries) return const string instead of just string?
Well no, you should make a copy and store it into a variable. There is copying there anyway and if you don't mind returning std::string, you probably don't have problems with performance issues. Regards, Pavol.