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

Subject: Re: [Boost-users] [mpl] BOOST_MPL_ASSERT_MSG for static_assert
From: Michael Powell (mwpowellhtx_at_[hidden])
Date: 2014-07-23 09:37:16

On Wed, Jul 23, 2014 at 8:30 AM, Stefan Näwe
<stefan.naewe_at_[hidden]> wrote:
> Am 23.07.2014 15:04, schrieb Michael Powell:
>> 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'
>>
>
> Try to play preprocessor yourself. How many commas do you
> count in the invocation of BOOST_MPL_ASSERT_MSG ?

Good eyes...

BOOST_MPL_ASSERT_MSG(
    (std::is_base_of<xnode, Node>::value)
    , "requested type is not a node"
    , (types<node_type>)
    );

Thank ye.

> Stefan
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