Message 261268 - Python tracker

Message261268

Author	eryksun
Recipients	Raúl Núñez de Arenas, eryksun, paul.moore, steve.dower, tim.golden, zach.ware
Date	2016-03-06.19:58:45
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1457294325.33.0.938747836746.issue26493@psf.upfronthosting.co.za>
In-reply-to

Content
When Python creates an exception generically from a Windows error code, it calls WinAPI FormatMessage with the flag FORMAT_MESSAGE_IGNORE_INSERTS. The reason for this is explained in a blog post written by Raymond Chen[1]: "when you are not in control of the message, you had better pass the FORMAT_MESSAGE_IGNORE_INSERTS flag." [1]: https://blogs.msdn.microsoft.com/oldnewthing/20071128-00/?p=24353 Some extension modules in the code base get this wrong. For example, ctypes.FormatError() doesn't use FORMAT_MESSAGE_IGNORE_INSERTS, so it fails to get the system error message for ERROR_BAD_EXE_FORMAT (193) and just returns its default string "<no description>": >>> ctypes.FormatError(193) '<no description>'

Content

When Python creates an exception generically from a Windows error code, it calls WinAPI FormatMessage with the flag FORMAT_MESSAGE_IGNORE_INSERTS. The reason for this is explained in a blog post written by Raymond Chen[1]: "when you are not in control of the message, you had better pass the FORMAT_MESSAGE_IGNORE_INSERTS flag."

[1]: https://blogs.msdn.microsoft.com/oldnewthing/20071128-00/?p=24353

Some extension modules in the code base get this wrong. For example, ctypes.FormatError() doesn't use FORMAT_MESSAGE_IGNORE_INSERTS, so it fails to get the system error message for ERROR_BAD_EXE_FORMAT (193) and just returns its default string "<no description>":

    >>> ctypes.FormatError(193)
    '<no description>'

History
Date	User	Action	Args
2016-03-06 19:58:45	eryksun	set	recipients: + eryksun, paul.moore, tim.golden, zach.ware, steve.dower, Raúl Núñez de Arenas
2016-03-06 19:58:45	eryksun	set	messageid: <1457294325.33.0.938747836746.issue26493@psf.upfronthosting.co.za>
2016-03-06 19:58:45	eryksun	link	issue26493 messages
2016-03-06 19:58:45	eryksun	create