Jeff King wrote:
> khash.h lets you instantiate custom hash types that map between two
> types. These are defined as a struct, as you might expect, and khash
> typedef's that to kh_foo_t. But it declares the struct anonymously,
> which doesn't give a name to the struct type itself; there is no
> "struct kh_foo". This has two small downsides:
>
> - when using khash, we declare "kh_foo_t *the_foo". This is
> unlike our usual naming style, which is "struct kh_foo *the_foo".
>
> - you can't forward-declare a typedef of an unnamed struct type in
> C. So we might do something like this in a header file:
>
> struct kh_foo;
> struct bar {
> struct kh_foo *the_foo;
> };
>
> to avoid having to include the header that defines the real
> kh_foo. But that doesn't work with the typedef'd name. Without the
> "struct" keyword, the compiler doesn't know we mean that kh_foo is
> a type.
One of the reasons why Linux doesn't do typedef.
--
Felipe Contreras
