What does the term “opaque type” mean in the context of “CFBundleRef opaque type”?

Question

Does someone have a good explanation of what an \"opaque type\" is? I saw that term in context of the CFBundleRef, where they were saying: \"CFBundleRef opaque type

Answer 1

It's a future-declared structure. For example:

typedef struct CFBundle *CFBundleRef;

Without the actual definition of "struct CFBundle", your code cannot access anything within a CFBundleRef pointer. This is opaque.