typedef void *HKEY;
typedef unsigned long DWORD;
typedef long LONG;
typedef const char *LPCSTR;
typedef HKEY *PHKEY;
#define HKEY_LOCAL_MACHINE ((HKEY)(unsigned long)0x80000002)
LONG RegOpenKeyExA(HKEY, LPCSTR, DWORD, DWORD, PHKEY);
void f(void) {
HKEY key;
RegOpenKeyExA(
HKEY_LOCAL_MACHINE,
"Software\\MyApp",
0, 0, &key
);
}