Question

I’m looking at LPSTR which is defined as

typedef char* PSTR, *LPSTR;

The documentation says that PSTR is an alias for LPSTR. Is the fact that the dereference operator is missing enough to tell me it’s an alias? How are alias’s declared? In other words if I change this to

typedef char* PSTR, PSTR2, *LPSTR;

Do I now have two alias’s? What if I add another dereferenced variable?

typedef char* PSTR, *LPSTR, *LPSTR2;

Answer 1

Nothing is missing. The whitespace around the asterisk doesn’t matter.

This:

typedef char* PSTR, *LPSTR;

is the same as

typedef char *PSTR, *LPSTR;

which in turn is the same as having

typedef char *PSTR;
typedef char *LPSTR;

Both define type alisaes for the type “pointer to char“, but there is no connection between them, the fact that they’re both declared with the same typedef doesn’t matter much, is mostly done when you want variants (with and without pointer) like so:

typedef struct {
  int x, y;
} Point, *PointPtr;

this, by the way, is a practice I really discourage (as is the code in the question itself), since “hiding the asterisk” is generally a bad idea. That asterisk matters, and having it present instead of being hidden in the type makes the code much clearer.