YES, you do. SCIP_CALL () is a global define, which handles the return codes of all methods which return a SCIP_RETCODE and should THEREFORE parenthesize each such method. SCIP_OKAY is the code which is returned if everything worked well; there are 17 DIFFERENT ERROR codes, see type_retcode.h.

Each method that calls methods which return a SCIP_RETCODE should itself return a SCIP_RETCODE. If this is not possible, use SCIP_CALL_ABORT () to catch the return codes of the methods. If you do not want to use this either, you have to do the exception handling (i.e. the CASE that the return code is not SCIP_OKAY) on your own.

Yes, you do. SCIP_CALL () is a global define, which handles the return codes of all methods which return a SCIP_RETCODE and should therefore parenthesize each such method. SCIP_OKAY is the code which is returned if everything worked well; there are 17 different error codes, see type_retcode.h.

Each method that calls methods which return a SCIP_RETCODE should itself return a SCIP_RETCODE. If this is not possible, use SCIP_CALL_ABORT () to catch the return codes of the methods. If you do not want to use this either, you have to do the exception handling (i.e. the case that the return code is not SCIP_OKAY) on your own.