Is typedef ever required in C?

Typedef is very useful for portable names, tag names (typedef struct foo Foo;) and keeping complicated (function) declarations readable (typedef int (*cmpfunc)(const void *, const void *);).

But are there situations in C where a typedef is really truly needed? Where you cannot accomplish the same by simple writing out the derived type.

To clarify a bit: I mean for language users, not implementers. The whole of stdint.h is a good example of the second category.

Conclusion

Thanks for all your input. I think I can summarise it as:

• The C99 library needs typedef to implement the various (u)intN_t types.
• On C89 you really want to use typedefs yourself to create similar portable types.
• You might need typedef when using the va_arg macro, but I doubt you will encounter these derivative types in practise.