Displays the message tag for each warning message of the C++ compiler front-end that can be suppressed with the -erroff option or made a fatal warning with the -errwarn option.
a can be either yes or no. The default is -errtags=no. Specifying -errtags is equivalent to specifying -errtags=yes.
Messages from the C++ compiler driver and other components of the compilation system do not have error tags, and cannot be suppressed with -erroff or made fatal with -errwarn.
-erroff, -errwarn