Re: C++ Template Virtual Function

From:
Vishal <vishalrawate6@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 4 Dec 2012 10:20:22 -0800 (PST)
Message-ID:
<ff53db41-a84b-4f99-af22-e867445fcf52@q5g2000pbk.googlegroups.com>

For reference, I repeat the getValue() code here:

        template<typename T>
        int getValue(std::list<T> &val) {
                if ( m_Type == eType::short ) val.push_back(boost::any_cast<short>(m_Value));
                if ( m_Type == eType::long ) val.push_back(boost::any_cast<long> (m_Value));
                if ( m_Type == eType::char ) val.push_back(boost::any_cast<char> (m_Value));

                return 0;
        }


Again, you are corrrect. I meant to place a double if statement.

if ( (m_Type == eType::short) && (m_Type == getType<T>() )

Yes, if this is OK regarding your app logic, you can do this. For this
you won't need the whole eType system though as boost::any knows its
stored type anyway:


I must be missing something. Boost any may know what type it but the
documentation doesn't specify a way to get that information. The
examples show the follow way to determine type. I really don't want
to throw exceptions for incorrect type cast.

try
{
    any_cast<const char *>(operand);
    return true;
}
catch(const boost::bad_any_cast &)
{
    return false;
}

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