[Python-Dev] Symbolic errno values in error messages

[Georg Brandl]

Yannick Gingras schrieb:
> "Alexandre Vassalotti" <alexandre at peadrop.com> writes:
> 
>>>> So now I am not sure what OP is proposing.  Do you want to replace 21
>>>> with EISDIR in the above?
>>>
>>> Yes, that's what I had in mind.
>>>
>>
>> Then, check out EnvironmentError_str in Objects/exceptions.c. You
>> should be able import the errno module and fetch its errorcode
>> dictionary.
> 
> It wasn't as hard as I expected.  It's the first time that I play with
> the Python C API; I didn't expect the API to be that high level.
> 
> I attached a patch to convert errno to its symbolic value when an
> EnvironmentError is printed.  Should attach it to a ticket on
> bugs.python.org?
> 
> I'm sure there is a style guide like PEP-8 for C code, feel free to
> point me to it because my patch is probably not fully style compliant.
> 
> With Emacs, doing
> 
>  M-x c-set-style python
> 
> doesn't seems to do the right thing.  Are you all using a bunch of
> shared settings in you .emacs files?

For new-style Python C files, this style definition works well:

(c-add-style
  "python-new"
  '((indent-tabs-mode . nil)
    (fill-column      . 78)
    (c-basic-offset   . 4)
    (c-offsets-alist  . ((substatement-open . 0)
                         (inextern-lang . 0)
                         (arglist-intro . +)
                         (knr-argdecl-intro . +)))
    (c-hanging-braces-alist . ((brace-list-open)
                               (brace-list-intro)
                               (brace-list-close)
                               (brace-entry-open)
                               (substatement-open after)
                               (block-close . c-snug-do-while)))
    (c-block-comment-prefix . "* "))
  )

This is a very crude hook that auto-selects the C style depending on
whether it finds a line starting with tab in the first 3000 characters
in the file:

(defun c-select-style ()
   (save-excursion
     (if (re-search-forward "^\t" 3000 t)
         (c-set-style "python")
       (c-set-style "python-new"))))
(add-hook 'c-mode-hook 'c-select-style)

HTH,
Georg