windows data types (typedef )

http://msdn.microsoft.com/en-us/library/aa383751%28VS.85%29.aspx

Overview of Windows API

7 functional categories of Win API

int WINAPI WinMain(HINSTANCE hinst, HINSTANCE hprev, LPSTR cp, int show) {....}

#define  WINAPI  __stdcall
typedef  HANDLE  HINSTANCE;
typedef  PVOID   HANDLE;
typedef  void*   PVOID;
typedef  CHAR*   LPSTR;
typedef  char    CHAR;

All window procedures share the same signature except for their name. There are four parameters. The header for any window procedure takes the form

BOOL CALLBACK nameWinProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)

 typedef  int           BOOL;
#define  CALLBACK      __stdcall
typedef  HANDLE        HWND;
typedef  unsigned int  UINT;
typedef  UINT_PTR      WPARAM;
typedef  unsigned int  UINT_PTR;
typedef  LONG_PTR      LPARAM;
typedef  long          LONG_PTR;

more details refer GAM666 introduction page
typedef can refer wikipidea/typedef