[ python-Bugs-980925 ] Possible contradiction in "extending" and
PyArg_ParseTuple()
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Sun Jun 27 20:33:04 EDT 2004
Bugs item #980925, was opened at 2004-06-27 20:02
Message generated for change (Comment added) made by tim_one
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Category: Documentation
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Submitted By: Brett Cannon (bcannon)
Assigned to: Nobody/Anonymous (nobody)
Summary: Possible contradiction in "extending" and PyArg_ParseTuple()
Initial Comment:
In section 1.3 of the "extending" tutorial (http://www.python.org/
dev/doc/devel/ext/backToExample.html), in the discussion of the
use of PyArg_ParseTuple() for a string argument, it says that "in
Standard C, the variable ... should properly be declared as "const
char *" ". But if you look at any example code (such as in section
1.7, which covers parsing arguments; http://www.python.org/dev/
doc/devel/ext/parseTuple.html) and the docs for
PyArg_ParseTuple() (found at http://www.python.org/dev/doc/
devel/api/arg-parsing.html) just use ``char *`` as the type for the
argument for a string.
Which is correct? I suspect that it is not required but more correct
to have the variables declared ``const char *`` since you are not
supposed to play with the string that is being pointed to (which is
probably why the Unicode arguments in the docs for
PyArg_ParseTuple() say it is ``const char *`` instead of just
``char *``). If this is true I will change the docs and the tutorial
to use ``const char *``. But if it isn't, I will rip out the line saying
that you should ``const char *`` since this is a contradiction at the
moment of recommended practice.
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>Comment By: Tim Peters (tim_one)
Date: 2004-06-27 20:33
Message:
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user_id=31435
Most of Python, and its docs, were written before C89
("Standard C") was required. const is used sporadically as a
result, mostly just in newer code and docs.
Changing examples to use const char * should be fine, as
that is best C practice. Just make sure the examples still
work <wink -- but sticking "const" in has a way of
propagating; e.g., once you have a const char *, you can't
pass it directly to a function taking a (non-const) char *
argument anymore>.
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