[pygame] Wiimote and I/O Questions

[Luke Paireepinart <rabidpoobear@xxxxxxxxx>]

Hey, some people on the list seemed pretty excited about the ctypes 
Wiimote code I was working on,
so I just wanted to let ya know that I'm done with finals (at last!) and 
I'm going to start work on this code some more,
as well as getting it working on other platforms too, I hope.
But I had a question:
I'm using ctypes to interface with the kernel32.dll on Windows XP.  I 
can use the CreateFile function to create a handle to a
file object that I can later pass to ReadFile to get the contents of the 
file.  The HID devices are mounted as special paths in the filesystem
that I can open in order to communicate with them.  The Wii Remote 
registers itself as an HID device, so I can talk to it in this way.
The only problem I can think of is that, as was mentioned in an earlier 
discussion, what should happen when reading data?
Should it block, or what?
Someone mentioned that on other OSes, such as Linux and MacOS (and I 
admit I'm ignorant of the details here)
that it's difficult to do overlapped input/output (which is where you 
call the file read, and you immediately get control returned
to you, and then later when you want the result of the read, you call 
GetOverlappedIOResult.)  and instead of doing that,
programmers for these OSes just use reads with a timeout.
Well, ironically, the ReadFile of the Windows kernel32.dll doesn't have 
a timeout that you can specify, except regarding
communications devices, and I don't believe that an HID device fits into 
this category (I think they mean if you have a handle
to a communications port, like COM1, etc).
Ideally I'd want the underlying Wii Remote communication code to work as 
similarly as possible on all platforms.

Now, I could do the following (in Windows)
1. call ReadFile with overlapped I/O.
2. while I'm getting an ERROR_IO_PENDING from GetLastError, sleep.
3. if slept longer than timeout, call CancelIO on the file to terminate 
the IO, and return.
4. if not slept longer than timeout, and not IO_PENDING, read in the data.

This would essentially behave the same way as a simple file read with a 
timeout, except (IMHO) extremely needlessly complicated.

So, finally, I get to my questions:
1. Is it really so bad to just have it run in a thread and use 
forever-blocking file reads (do these use a lot of the CPU?)
2. Does anyone know of a windows dll command that will read from a file 
with a timeout?
3. Once the device path is known, could the pyWin32 module be of any 
help in reading/writing to these files?

One more thing to note:
I would just use python's file() function to open the device, once its 
pathname was known (which takes a bit of fiddling with the HID.dll)
but whenever I try this, Python doesn't find the file and raises an error:
IOError: [Errno 2] No such file or directory: 
'\\\\?\\hid#hid_keyboard#2&10d82c60&0&0000#{4d1e55b2-f16f-11cf-88cb-001111000030}'
(full traceback omitted because it's unimportant in this case. the error 
is just raised on the statement f = file(detail.DevicePath) which 
contains the above string.)

and a final question...
4.  Is there a special procedure to go about opening these types of 
files, that, if followed, would let me just use Python and bypass
the whole CreateFile/WriteFile/ReadFile kernel stuff?

Feel free to direct me to a different mailing list.
Thanks for taking the time to read this,
-Luke