When a SSA-NAME3 Service is called by an application, that Service may in turn call other SSA-NAME3 Services or Modules.

Primary response codes are generated by the Service called by the application, while Secondary response codes are generated by a secondary Service or Module that detected the original problem. Secondary response codes therefore reflect the actual cause of the problem while Primary response codes tell the application how to act on the problem.

In this example the Primary response code is 070046 from NAMESET. This was the result of the 020138 Secondary response code from the Formatting Service which actually detected the loop.

The module that first detects a problem sets both the Primary and Secondary response codes. The Secondary response code is then not changed from that point on.

If the severity of that Secondary response code is either ’Error’ or ’Fatal’, control is returned to the calling Service immediately so that the Primary response code reflects the severe error. Otherwise, if the severity was a ’Warning’ or ’Message’, processing continues. If a further error is detected, the Primary response code is overwritten with the most recent (non-severe) error. When control finally returns to the original Service, it will set a new Primary response code indicating the error.