Re: e and pi

[David Kastrup <dak@gnu.org>]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Helmut Eller <eller.helmut@gmail.com>
>> Date: Fri, 17 Sep 2010 18:18:25 +0200
>> 
>> >   (defun froob (argv)
>> >      (lambda (f) (cons f argv)))
>> >
>> > and have that fail, because "argv" is a defvar defined in startup.el.
>> 
>> I once had a function with an argument called system-name.  Suddenly
>> Emacs started to complain that some files are locked by some other user.
>> How many people now that system-name is a global variable and used by
>> the file-locking code?  The lesson is that Emacs should not pre-define
>> global variables with names that are likely candidates for local
>> variables.
>
> What you describe as a big surprise is actually known to every C/C++
> programmer: some names are "reserved by the implementation" and should
> not be used by the application code.

For a function argument?  I beg to differ.  The only way to get a
conflict is using extern declarations.

And identifiers reserved by the implementation start with two
underlines.

-- 
David Kastrup