o <B>Tcl_RegExpCompile</B>;  it is not safe to
retain these values for long periods of time.
<P>
<B>Tcl_RegExpExec</B> executes the regular expression pattern matcher.
It returns 1 if <I>text</I> contains a range of characters that
match <I>regexp</I>, 0 if no match is found, and
-1 if an error occurs.
In the case of an error, <B>Tcl_RegExpExec</B> leaves an error
message in the interpreter result.
When searching a string for multiple matches of a pattern,
it is important to distinguish between the start of