In any RETURN statement, whether it returns an ERROR or not, you can return a text string to the calling procedure. This string is accessible in the caller through the RETURN-VALUE built-in function. Thus, a procedure can use a single RETURN statement to raise the ERROR condition in the caller, return a message, or both. This is the syntax of the RETURN statement:

Likewise, the caller can check for the ERROR-STATUS:ERROR condition, or a RETURN-VALUE, or both, depending on the agreement between caller and callee as to how they communicate with one another. The RETURN-VALUE function retains its value even through multiple RETURN statements. Thus, while it is not required, it is advisable always to have a RETURN statement at the end of every procedure, if only to clear the RETURN-VALUE. A simple RETURN statement is the same as RETURN "". If you want to pass the RETURN-VALUE up the call stack, you should do this explicitly using the statement RETURN RETURN-VALUE.

The same is true of the RETURN option as part of the ON phrase in a block header. It can return a return-value, raise ERROR, or both.