Class error

dlib/error.h:62–178

the base exception class

    // the base exception class
    class error : public std::exception
    {
        /*!
            WHAT THIS OBJECT REPRESENTS
                This is the base exception class for the dlib library.  i.e. all 
                exceptions in this library inherit from this class.
        !*/

    public:
        error(
            error_type t,
            const std::string& a
        ): info(a), type(t) {}
        /*!
            ensures
                - #type == t
                - #info == a
        !*/

        error(
            error_type t
        ): type(t) {}
        /*!
            ensures
                - #type == t
                - #info == ""
        !*/

        error(
            const std::string& a
        ): info(a), type(EUNSPECIFIED) {}
        /*!
            ensures
                - #type == EUNSPECIFIED
                - #info == a
        !*/

        error(
        ): type(EUNSPECIFIED) {}
        /*!
            ensures
                - #type == EUNSPECIFIED
                - #info == ""
        !*/

        virtual ~error(
        ) noexcept {}
        /*!
            ensures
                - does nothing
        !*/

        const char* what(
        ) const noexcept
        /*!
            ensures
                - if (info.size() != 0) then
                    - returns info.c_str()