Re: Check for redundancy

[Yuri Khan <yuri.v.khan@gmail.com>]

On Fri, Jul 3, 2015 at 12:41 PM, Eli Zaretskii <eliz@gnu.org> wrote:

>> Nowadays (since ≈2002?) the SDK defines a strict mode, where different
>> kinds of handles become pointers to different tag structure types:
>>
>> struct tagWND;  // declared but not defined
>> typedef struct tagWND* HWND;
>
> Perhaps in MSVC compiler, not in MinGW.  With MinGW, something similar
> happens only if you compile with -DSTRICT (which is rarely, if ever,
> done).  And even in MSVC headers I see something significantly
> different from what you show above, and it's also conditioned by
> STRICT being defined.

Yes. -DSTRICT has been the default setting for new projects created in
MSVC++ since version 7 or so. Is there some problem enabling STRICT on
MinGW, or a reason why it is done rarely?

How is it significantly different? Here’s what I see in some ancient copy:

// 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

// in windef.h
DECLARE_HANDLE            (HWND);
DECLARE_HANDLE            (HHOOK);

OK, it’s not an undefined struct, it’s a struct with a unique type
name and a single unused int field. This does not affect the type
system, as neither C nor C++ have structural typing. Leaving the
struct undefined would probably be a bit safer.