[C++-sig] Apparent bug

[David Abrahams]

Re-posting the same report doesn't make it any clearer what your problem
is. Also note that your tabs are stripped so that there's no indentation.
Is there a bug in the library?

Oh... after re-reading about 5 times I see what you're talking about. This
is a VC++ compiler bug, not a library bug. VC++ incorrectly propagates the
constness of declared argument types into the type of the function
signature. Nothing you can do about it, sorry (other than declaring the
function initially with a prototype using a non-const argument -- you can
still make the function definition use a const argument).

-Dave



----- Original Message -----
From: "Victor A. Wagner, Jr." <vawjr at rudbek.com>
To: <c++-sig at python.org>
Sent: Wednesday, July 10, 2002 2:42 PM
Subject: [C++-sig] Apparent bug


> Using the commented out signature (the one with  .............., const
> std::size_t key,............)
> causes errors compiling on VC++.NET
> It's not clear why declaring the key const should (in the philosophical
> sense) cause any difficulties.  following the actual thread
> of errors was beyond our abilities at the time.  Of course, the original
> "error" didn't mention const anywhere, which didn't make finding the
> problem any easier.
>
> <rant>I sure wish the .NET compiler would give the "called from" trace
back
> on all of it's errors/warnings to facilitate finding the perceived
> problems(like VC++6 did).  This one we chased for over  an hour</rant>
>
> TimeStamps is equivalent to std::vector<double>
> The error does NOT occur until        time_stamp.def(set_ts_item,
> "__setitem__");       is added to the source.  That is, if the line is
> removed, there is no error, but of course, we can't access set_ts_item
either.
> ========================================================
>
> // Sets the item corresponding to key in the map.
> //void set_ts_item( TimeStamps& self, const std::size_t key, const
double&
> value)
> void set_ts_item( TimeStamps& self, std::size_t key, const double& value)
> {
> self.at(key) = value;
> }
>
> #include <boost/python/class_builder.hpp>
> namespace python = boost::python;
> BOOST_PYTHON_MODULE_INIT(PythonTest)
> {
> // Create an object representing this extension module.
> python::module_builder this_module("PythonTest");
> // TimeStamps
> python::class_builder<TimeStamps> time_stamp(this_module, "TimeStamps");
> time_stamp.def(boost::python::constructor<>());
> time_stamp.def(&TimeStamps::size, "__len__");
> time_stamp.def(get_ts_item, "__getitem__");
> time_stamp.def(set_ts_item, "__setitem__");
> }
> Victor A. Wagner Jr.      http://rudbek.com
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> The five most dangerous words in the English language:
>                "There oughta be a law"
>
>
>
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