FutureWarning/OverFlow error and 0xffff0000

Mark Hammond mhammond at skippinet.com.au
Fri Feb 21 04:41:26 CET 2003

Richard Jones wrote:
> My code has a couple of instances of 0xffff0000 in it - they're bitmask flags 
> to windows calls. Up until 2.3, all was well. Now in 2.3, I get warnings 
> "FutureWarning: hex/oct constants > sys.maxint will return positive values in 
> Python 2.4 and up" about that value. The first solution I came up with was to 
> suppress the warning before I import the specific module that has the 
> literal.
> I fleetingly noticed someone suggest that I use a long int literal instead: 
> 0xffff0000L
> No dice. On older versions of Python, this generates an "OverflowError: long 
> int too large to convert to int".
As the value is a bitmask, you may not want a long - the value is going 
to end up in a C 'int'.

I believe the 'correct' solution is to use a decimal literal - -65536 in 
this case.

It is unclear what Python 2.4 will do about these constants.  This has 
come up on python-dev before, but been punted.  The win32 extensions in 
particular would be burdended by this, as we use *lots* of hex 
constants, typically generated by h2py.py.

Keep you eye on the python-dev summaries post the 2.3 release - it will 
come up again.


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