On Sat, Nov 16, 2013 at 11:18 AM, Mathias Gaunard wrote:

On 16/11/2013 01:02, Mostafa wrote:

...

#include #include <utility>

int main() { BOOST_IDENTITY_TYPE(( std::pair const )) x; // This compiles, so the const qualification in the // above macro parameter is ignored. x = std::make_pair(0,1);

return 0; }

The omission of const qualification in BOOST_IDENTITY_TYPE types is undocumented. This omission maybe deduced from the documented implementation, but, as noted, that is not part of the library api and is subject to change. I therefore propose that this behaviour be documented as part of the library's public api.

That looks like a bug.

Is there a way to extract the cv-qualifier from a function parameter type at compile-time? some_mata_function::type // evaluates to `int const` not just `int` Right now I do the following which looses the cv-qualifier (I also tried to program my own meta-functions but I wan't able to retain the cv-qualifier). boost::function_traits::arg1_type // evaluates to `int` and not to `int conat` :( Thanks. --Lorenzo

On Tue, 03 Dec 2013 11:23:46 -0800, Krzysztof Czainski <1czajnik@gmail.com> wrote:

2013/12/3 Lorenzo Caminiti

...

On Sat, Nov 16, 2013 at 11:18 AM, Mathias Gaunard wrote:

...

On 16/11/2013 01:02, Mostafa wrote:

...

#include #include <utility>

int main() { BOOST_IDENTITY_TYPE(( std::pair const )) x; // This compiles, so the const qualification in the // above macro parameter is ignored. x = std::make_pair(0,1);

return 0; }

The omission of const qualification in BOOST_IDENTITY_TYPE types is undocumented. This omission maybe deduced from the documented implementation, but, as noted, that is not part of the library api

and

...

is subject to change. I therefore propose that this behaviour be documented as part of the library's public api.

That looks like a bug.

Is there a way to extract the cv-qualifier from a function parameter type at compile-time?

some_mata_function::type // evaluates to `int const` not just `int`

Right now I do the following which looses the cv-qualifier (I also tried to program my own meta-functions but I wan't able to retain the cv-qualifier).

boost::function_traits::arg1_type // evaluates to `int` and not to `int conat` :(

how about (not tested): boost::remove_reference< boost::function_traits::arg1_type >::type

Pointers should be used instead. References will lead to bugs because of reference collapsing when add_reference is used. For example: BOOST_IDENTITY_TYPE(( std::pair & )) x; will be incorrectly deduced as std::pair