A <A HREF="../guide/modes.html#mode_tags">mode tag</A>.</TD>
    </TR>
    <TR>
        <TD VALIGN="top"><I>Ch</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
        <TD>The character type</TD>
    </TR>
    <TR>
        <TD VALIGN="top"><I>Tr</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
        <TD>The traits type</TD>
    </TR>
    <TR>
        <TD VALIGN="top"><I>Alloc</I></TD><TD WIDTH="2em" VALIGN="top">-</TD>
        <TD>A standard library allocator type (<A CLASS="bib_ref" HREF="../bibliography.html#iso"