What is the difference when using @class or #import in objective-c?
I have seen various tutorials and only a few use @class while most of the others use #import.
+3
A:
@class doesn't import the file, it just says to the compiler "This class exists even though you don't know about it, don't warn me if I use it". #import actually imports the file so you can use all the methods and instance variables. @class is used to save time compiling (importing the whole file makes the compile take more time). You can use #import if you want, it will just take longer for your project to build.
nevan
2010-07-12 13:07:00
Sometimes, particularly in the case of circular references, you absolutely cannot use #import. @class is a forward declaration of a class, and since it doesn't define the class, can break circular references.
Jay O'Conor
2010-07-12 17:57:47
I thought that #import protected against those, by only adding each file one time.
nevan
2010-07-12 18:26:57