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Re: AW: Conceptual Patch - Handle wrapper class

From: Joseph Galbraith <galb_at_vandyke.com>
Date: Tue, 15 Mar 2011 11:39:21 -0600

On 03/15/2011 03:48, Oto BREZINA wrote:
> Dear Jens,
> On 2011-03-15 10:23, Jens Geyer wrote:
>>> I just read some articels about NULL vs. INVALID_HANDLER_VALUE and
>>> author states that all new (not existing in WIN16) methods are NULL on
>>> error.
>> The author is probably wrong here.
>> If in doubt, which values are returned, I would suggest to ask MSDN about that.
>> Although there are also quite a few errors in there, this is the reference I would start with.
> I use MSDN as first point to get info about parameters and returned
> values of course. If INVALID_HANDLE_VALUE is just for compatibility with
> win16 code or not, is only side question.
> Main questions (already anwsered) were:
> Can be NULL valid? Can be INVALID_HANDLE_VALUE valid?
> Just side question:
> Do you know any method which has been added to win32 with returning
> INVALID_HANDLE_VALUE (or not NULL) on error?
> Do known any Win16 method returning handle to do return NULL (or not

Neither NULL nor INVALID_HANDLE_VALUE are ever a valid value for
a handle (in fact, no odd number is ever a valid handle value.)

CreateFile() return INVALID_HANDLE_VALUE to indicate failure.

Other APIs return NULL to indicate failure (CreateEvent for example.)

I believe this implies that anything handling handles in a generic
fashion would need to check for either INVALID_HANDLE_VALUE or
NULL to indicate an invalid handle.

CloseHandle() should never be called with either INVALID_HANDLE_VALUE or



> sorry I forgot tried to write it instead of copy-paste. My e-mail client
> won't compile with any value ;)
>> JensG
> Oto


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Received on 2011-03-15 18:39:28 CET

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