Re: [ctypes-users] destroying a window on windows

[Michael C <mys...@gm...>]

more importantly, how do i switch to the proper thread?

thanks!

On Wed, May 17, 2017 at 7:14 PM, Michael C <mys...@gm...>
wrote:

> where can i read up on what a thread is and what it does?
>
> Thanks!
>
> On Wed, May 17, 2017 at 7:12 PM, eryk sun <er...@gm...> wrote:
>
>> On Wed, May 17, 2017 at 11:10 PM, Michael C
>> <mys...@gm...> wrote:
>> > Apparently even though the MSDN says, given a handle, it would kill the
>> > window, but it doesn't do that for me. Am I doing it properly?
>> >
>> > import time
>> > import ctypes
>> > User32 = ctypes.WinDLL('User32', use_last_error=True)
>> >
>> > handle = User32.GetForegroundWindow()
>> > print(handle)
>> > time.sleep(2)
>> > User32.DestroyWindow(handle)
>>
>> You're not checking the BOOL return value to see whether the call
>> succeeded. If it failed, you need to raise an exception for the
>> thread's last error value. Do this in a ctypes errcheck function. For
>> example:
>>
>>     def _check_bool(result, func, args):
>>         if not result:
>>             raise ctypes.WinError(ctypes.get_last_error())
>>         return args
>>
>>     User32.DestroyWindow.errcheck = _check_bool
>>
>> With this check in place, if User32.DestroyWindow(handle) fails,
>> you'll get an idiomatic exception. Chances are that the foreground
>> window doesn't belong to your thread, and you haven't read the fine
>> print in the remarks on MSDN:
>>
>>    A thread cannot use DestroyWindow to destroy a window created by a
>> different thread.
>>
>> Thus it's probably failing with ERROR_ACCESS_DENIED (5). Try sending
>> the window a WM_CLOSE message instead.
>>
>
>