Method geterror

tests/osl/UnitTestOSL.h:37–49

    inline bool haserror() const { return m_errormessage.size(); }
 
    std::string geterror(bool erase = true)
    {
        std::string s;
        if (erase)
        {
            std::swap(s, m_errormessage);
        }
        else
        {
            s = m_errormessage;
        }
        return s;
    }

private:
    std::string m_errormessage;