What is the difference between HANDLE and HWND

[abdul]

What is the difference between HANDLE and HWND?

[parksie]

Technically, not much. Look at the definition for HWND to see how similar all the H* types are. Conceptually, quite a lot is different. I'm not sure if you can pass an HWND to a HANDLE or vice versa but possibly.

[Yonatan]

To elaborate on what parksie said: HANDLE is a handle to any Kernel32 object, while HWND is a handle to a specific User32 object (window).
They're not parts of the same Win32 library, so I would say the chance that you can use a HANDLE value as a HWND and vice versa is pretty, well, tiny

[abdul]

I used handle on just one time when creating a file.
Everywehre else, for graphics or windws creation, I use hwnd

So is handle used to works with the kernel (files manipulation).

[Zaei]

Im pretty sure that you can pass an HWND as a HANDLE. Someone check the typedefs (I cant at the moment, 16-bit DOS compiler only =( ). I THINK that typedef DWORD HANDLE; and typedef HANDLE HWND; should exist.

Z.

[parksie]

A handle is actually a pointer to a struct, I think.

[Yonatan]

Originally posted by parksie
A handle is actually a pointer to a struct, I think.

From what I remember, it goes something like this:
There are two compile modes - STRICT mode and non-STRICT mode. (In VC++ 5, non-STRICT was the default, and in VC++ 6, STRICT was the default.)

In non-STRICT mode, the handles are defined like this:

typedef void* HANDLE;
typedef void* HWND;
// etc.

In STRICT mode, the handles are defined like this:

typedef struct __tagHANDLE { DWORD __unused; } *HANDLE;
typedef struct __tagHWND { DWORD __unused; } *HWND;

But I'm not sure...
Sec, checking.
...
...
...
AHA! There it is, in winnt.h:

#ifdef STRICT
typedef void *HANDLE;
#define DECLARE_HANDLE(name) struct name##__ { int unused; }; typedef struct name##__ *name
#else
typedef PVOID HANDLE;
#define DECLARE_HANDLE(name) typedef HANDLE name
#endif

And in other header files:

DECLARE_HANDLE(HWND);
DECLARE_HANDLE(HGDIOBJ);
// etc.

Which means the handles are declared like this:

// STRICT mode:
typedef void* HANDLE;
typedef struct HWND__ { int unused; } *HWND;
typedef struct HGDIOBJ__ { int unused; } *HGDIOBJ;
// etc.

// Non-STRICT mode:
typedef PVOID HANDLE; // PVOID is pretty much the same as void* though
typedef HANDLE HWND;
typedef HANDLE HGDIOBJ;
// etc.

Whew, that was fun