Catching a pywintypes.api_error excpeption?

Mark Hammond mhammond at
Fri Aug 2 15:25:10 CEST 2002

Peter Hansen wrote:
> Derek Basch wrote:
>>Can someone tell me how to catch this exception with a
>>try, except clause:
>>    SetCommState(self.handle, dcb)
>>pywintypes.api_error: (87, 'SetCommState', 'The
>>parameter is incorrect.')
>>every exception I have previously worked with has been
>>a class such as IOError. How do i catch this one?
> As with "except IOError", just use the name of the class:
> try:
>     SetCommState(self.handle, dcb)
> except pywintypes.api_error:
>     print 'spam spam spam spam'

It *should* be pywintypes.api_error, but for historical reasons this is 
not correct :(  I have finally fixed it so the exception printed is 
'pywintypes.error', which is actually an exception you can catch.

In the win32 extensions, every module exposes an 'error' object - and 
all are the exact same error object.  Thus, as these functions come from 
win32file, you typically catch win32file.error, but pywintypes.error, 
and basically win32*.error, will all work.


 >>> pywintypes.error is win32file.error

> (Although this sounds more like an exception coming from
> a bug, not a runtime condition that you would want to catch
> like an IOError.)

No, this is just the standard exception raised by the win32 exceptions 
whenever the underlying win32 API function fails.  The error code is in 
the exception.


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