* 'Axel Wagner' via golang-nuts <golang-nuts@googlegroups.com> [210607 19:06]: > Well, it seems a bad idea to say that interfaces are implicitly pointers > then. That seems to indicate that Rob's original phrasing is indeed an > important clarification - the language behaves as if the value contained in > them is copied when the interface value is copied.
I agree with most of what you are saying to Robert Engels, but I disagree with this. The FAQ needs to make it clear that making a copy of the value happens when assigning a concrete value to an interface and when extracting a concrete value from an interface, but that the interface passed around does _not_ require the allocation overhead of copying the concrete value every time the interface is copied (even if it behaves, whenever the interface is used, as if a copy is made). It is clear from this thread that this is a confusing topic, and also that programmers new to Go are reading this FAQ entry and believing, incorrectly, that to optimize memory allocations they should use pointers when it is not necessary to do so. In other words, there are two distinct aspects that both need to be expounded in the FAQ: the external behavior and the performance-related consequences. People are jumping to the wrong conclusion because the FAQ says "copying the interface value makes a copy of the struct". This is simply untrue, and not necessary according to the language spec. The correct statement is that "copying the interface value behaves as if the struct is copied without actually needing to make a new copy of the struct". That second part is important. ...Marvin -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/20210608004229.3s3ftgrdy47guhic%40basil.wdw.
