FutureWarning question

[A. Lloyd Flanagan]

Mike <mike at nospam.com> wrote in message news:<16mnetilcmds6.1apnyu46tbjpw.dlg at 40tude.net>...
> I ran across the message below in 2.3.2 today. These are the lines of code:
> 
>    402: if m1_hi >> 15 & 0x0001 == 1:
>    403:    m1_hi = m1_hi | 0xFFFF0000
>    404: if m1_lo >> 15 & 0x0001 == 1:
>    405:    m1_lo = m1_lo | 0xFFFF0000
> 
> This is the warning message:
> 
>    pwg.py:403: FutureWarning: hex/oct constants > sys.maxint will return 
>    positive values in Python 2.4 and up
>       m1_hi = m1_hi | 0xFFFF0000

sys.maxint is the largest number that will fit into an int data type. 
Although your constant is 32 bits, the high bit is set, so it gets
interpreted as a negative number.

>>> x = 0xFFFF0000
>>> x
-65536

In future versions of python, constants which are larger than
sys.maxint will not be interpreted as negative, but will automatically
be promoted to a long integer.  The distinction between the two
integer types will pretty much disappear.

So, your constant will evaluate to a positive long integer
(4294901760L).  Since you're using it as a bit mask, and not a number,
I don't think it will make a difference for your application.  But the
compiler can't tell for sure, so it warns you anyway.