n <B>Tcl_RegExpMatch</B>
returns -1 and leaves an error message in the interpreter result.
<B>Tcl_RegExpMatchObj</B> is similar to <B>Tcl_RegExpMatch</B> except it
operates on the Tcl values <I>textObj</I> and <I>patObj</I> instead of
UTF strings.
<B>Tcl_RegExpMatchObj</B> is generally more efficient than
<B>Tcl_RegExpMatch</B>, so it is the preferred interface.
<P>
<B>Tcl_RegExpCompile</B>, <B>Tcl_RegExpExec</B>, and <B>Tcl_RegExpRange</B>
provide lower-level access to the regular expression pattern matche