Re: Warning with clang, error with gcc : attached files

[David Chisnall]

On 30/04/2019 15:34, Bertrand Dekoninck wrote:
> OK, thanks for your quick answer. I don't see any either, but I could 
> try to modify NSButtonCell.h locally to have this method public. Maybe I 
> need more help.

Normally, the fix for this kind of thing is to declare a category on 
NSButtonCell that exposes the method that you want.  It's somewhat 
fragile, so best practice would be to have a dynamic check in your 
+initialize that checks that the method does exist.

> Netherletheless, it doesn't explain why clang don't throw an error here. 
> And I've got several warnings of this kind when compiling rik.theme. I 
> suspect this is'nt the only private method that has be used is the rest 
> of the code.

Clang doesn't give an error because it's well-defined behaviour: the 
method will be assumed to return id and will be called assuming all 
parameters are of type id, unless otherwise specified.  That's almost 
certainly wrong, which is why it's a warning.

In ARC mode, this is explicitly a failure (even if the calling 
convention is correct, the memory ownership semantics are unknown) and 
this is one of the many reasons why anyone using Objective-C in 2019 
should be using ARC for almost everything.

David