How to get rid of FutureWarning: hex/oct constants...
Bengt Richter
bokr at oz.net
Thu Mar 24 22:35:29 EST 2005
On Thu, 24 Mar 2005 23:21:39 -0000, Grant Edwards <grante at visi.com> wrote:
>How do I get rid of the following warning?
>
> <path>.py:233: FutureWarning: hex/oct constants > sys.maxint will return positive values in Python 2.4 and up
> fcntl.ioctl(self.dev.fileno(),0xc0047a80,struct.pack("HBB",i,0,0))
>
>I tried using 0xc0047a80L. That got rid of the warning, but
>then I got an exception when fcntl.ioctl() was called because
>the long int was too large to be converted to an int.
>
Lobby for a PEP for numeric literals allowing representation
of negative numbers without writing a unary minus expression.
E.g.,
16xfc0047a80
would be explicitly negative and would not overflow 32-bit representation.
The corresponding positive value
16x0c0047a80
would overflow, of course, which would be proper.
Some discussion, including analogous spellings for other bases:
http://groups-beta.google.com/group/comp.lang.python/msg/c23131df1e919435
In the meantime, maybe (ugh):
Python 2.3.2 (#49, Oct 2 2003, 20:02:00) [MSC v.1200 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> -2*0x40000000+0x40047a80
-1073448320
>>> hex(-2*0x40000000+0x40047a80)
__main__:1: FutureWarning: hex()/oct() of negative int will return a signed string in Python 2.4
and up
'0xc0047a80'
That "signed string" is a unary minus expression using an absolute value forced by the inadequacy
of the literal representation syntax.
IOW, IMO '-' + hex_literal_of(abs(x)) is not a decent hex_literal_of(-x) !!
Urk and argh...
Regards,
Bengt Richter
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