Is it a good idea to typedef pointers?
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.
Not in my experience. Hiding the '*' makes the code hard to read.
The only time I use a pointer inside the typedef is when dealing with pointers to functions:
typedef void (*SigCatcher(int, void (*)(int)))(int);typedef void (*SigCatcher)(int);SigCatcher old = signal(SIGINT, SIG_IGN);Otherwise, I find them more confusing than helpful.
The struck-out declaration is the correct type for a pointer to the
signal() function, not of the signal catcher. It could be made clearer (using the corrected SigCatcher type above) by writing: typedef SigCatcher (*SignalFunction)(int, SigCatcher);Or, to declare the signal() function:
extern SigCatcher signal(int, SigCatcher);That is, a SignalFunction is a pointer to a function which takes two arguments (an int and a SigCatcher) and returns a SigCatcher. And signal() itself is a function which takes two arguments (an int and a SigCatcher) and returns a SigCatcher.