Is it a good idea to typedef pointers?

Question

I looked through some code and noticed that the convention was to turn pointer types like

SomeStruct*  

into

typedef SomeStruct* pSomeStruct; 

Is there any merit to this?

Answer 1

Not in my experience. Hiding the '*' makes the code hard to read.

Answer 2

This can be appropriate when the pointer itself can be regarded as a "black box", that is, a piece of data whose internal representation should be irrelevant to the code.

Essentially, if your code will never dereference the pointer, and you just pass it around API functions (sometimes by reference), then not only does the typedef reduce the number of *s in your code, but also suggests to the programmer that the pointer shouldn't really be meddled with.

This also makes it easier to change the API in the future if the need arises. For instance, if you change to using an ID rather than a pointer (or vice versa) existing code won't break because the pointer was never supposed to be dereferenced in the first place.