Re: [Boost-users] [mpl] BOOST_MPL_ASSERT_MSG for static_assert

Subject: Re: [Boost-users] [mpl] BOOST_MPL_ASSERT_MSG for static_assert
From: Krzysztof Jusiak (krzysztof_at_[hidden])
Date: 2014-07-23 09:31:26

Hi Michael,

You need brackets around 'is_base_of' expression , because there is a colon
in it.
"request type is not a node" has to be changed to be a legal C++ identifier
token as well (
http://www.boost.org/doc/libs/1_55_0/libs/mpl/doc/refmanual/assert-msg.html
).

BOOST_MPL_ASSERT_MSG(
    (std::is_base_of<xnode, Node>::value)
    , requested_type_is_not_a_node
    , (types<node_type>)
    );

Kris

On Wed, Jul 23, 2014 at 2:04 PM, Michael Powell <mwpowellhtx_at_[hidden]>
wrote:

> Hello,
>
> I would like to add some diagnostic messages during compile time,
> potentially enumerating one or more types as well.
>
> static_assert is great for simple messages but falls a bit short due
> to inability to list types and such.
>
> I wonder if BOOST_MPL_ASSERT_MSG is the right answer, however, I am
> getting the following errors:
>
> BOOST_MPL_ASSERT_MSG(
>     std::is_base_of<xnode, Node>::value
>     , "requested type is not a node"
>     , (types<node_type>)
>     );
>
> 1>i:\source\kingdom software\cppxml\xml\domain\parts\xnode.h(111):
> warning C4002: too many actual parameters for macro
> 'BOOST_MPL_ASSERT_MSG'
>
> It's an error message, but not the one(s) I am expecting. Do I need to
> enable something, preprocessor definition, something like that?
>
> Best regards,
>
> Michael Powell
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