beginning of the string or after a newline character.
For historical compatibility reasons, @samp{^} can be used only at the
-beginning of the regular expression, or after @samp{\(} or @samp{\|}.
+beginning of the regular expression, or after @samp{\(}, @samp{\(?:}
+or @samp{\|}.
@item @samp{$}
@cindex @samp{$} in regexp