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struct obj {
  int i;
  float f;
};
typedef struct obj *ObjectPtr;
 
void func(const ObjectPtr o) {
  /* Can actually modify o's contents, against expectations. */
}

struct obj {
  int i;
  float f;
};
typedef struct obj Object;
 
void func(const Object *o) {
  /* Cannot modify o's contents. */
}

#include <Windows.h>
/* typedef char *LPSTR; */
 
void func(const LPSTR str) {
  /* Can mutate str's contents, against expectations. */
}

#include <Windows.h>
/* typedef const char *LPCSTR; */
 
void func(LPCSTR str) {
  /* Cannot modify str's contents. */
}

#include <Windows.h>
/*
  typedef struct tagPOINT {
    long x, y;
  } POINT, *LPPOINT;
*/
 
void func(const LPPOINT pt) {
  /* Can modify pt's contents, against expectations. */
}

#include <Windows.h>
/*
  typedef struct tagPOINT {
    long x, y;
  } POINT, *LPPOINT;
*/
 
typedef const POINT *LPCPOINT;
void func(LPCPOINT pt) {
  /* Cannot modify pt's contents. */
}