Issue 1483963: struct.unpack problem with @, =, < specifiers (original) (raw)

Issue1483963

Created on 2006-05-08 17:05 by chrish42, last changed 2022-04-11 14:56 by admin. This issue is now closed.

Messages (4)
msg28447 - (view)	Author: Christian Hudon (chrish42) *	Date: 2006-05-08 17:05
When using struct to unpack floats, I'm getting inconsistent results when using the '<d' specification instead of '@d' on a little-endian machine (Intel). Here's a short python snippet that demonstrates the problem. import sys, struct s = '\x00\x00\x00\x00\x00\x00\xf8\x7f' >>> sys.byteorder 'little' # This is correct... >>> struct.unpack('@d', s) (nan,) # These should be equivalent for unpacking a single # double on little-endian arch... but they're not. >>> struct.unpack('<d', s) (inf,) >>> struct.unpack('=d', s) (inf,)
msg28448 - (view)	Author: Michael Hudson (mwh)	Date: 2006-05-10 12:17
Logged In: YES user_id=6656 Can you try Python from svn HEAD? Or did you?
msg28449 - (view)	Author: Christian Hudon (chrish42) *	Date: 2006-05-10 14:24
Logged In: YES user_id=980271 I had tried with 2.3.5 and 2.4.1 and the bug was present in both versions. I just tried with svn HEAD, and the bug is fixed there (at least in the revision that I tried). It'd be nice if this bug fix could be included in the next 2.4 point release, assuming the fix is not too complicated. Is there a process for nominating bugfixes for the main-2.4 branch?
msg28450 - (view)	Author: Michael Hudson (mwh)	Date: 2006-05-10 14:30
Logged In: YES user_id=6656 I'm glad my fix worked. I'm not personally inclined to port the fixes to the 2.4 branch, as they are indeed fairly involved.