Two system variables in Oracle that describe the error message (cainiao-level)

We often handle errors like this in Oracle stored procedures:
Declare
V_errorno number (10 );
V_errormsg varchar2 (255 );
Begin
-- Some SQL here
Exception
When others then
V_errorno: = sqlcode;
V_errormsg: = sqlerrm;
Rollback;
Return;
End;

Although when others then can receive all the errors, how do we know why the error is caused? The sqlcode and sqlerrm system variables provide the last errorCodeAnd error description. In this way, the cause of the error can be located faster during debugging.