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caddr_t srv_make_error (char *code, char *msg);
void sqlr_error (char *code, char *msg,...);
void sqlr_resignal (caddr_t err);

An error object is a three element array of type DV_ARRAY_OF_POINTER , consisting of the number 3, the SQL state and the message. The control flow in case of errors signalled inside VSEs is a longjmp to an outer context, typically that of the calling stored procedure or top level query. The condition is there handled or sent to the next level up, ultimately to the ODBC, JDBC or Web client. Executing a SQL statement inside a VSE always returns and never exits the VSE by longjmp. Thus the VSE gets a first look at all SQL errors caused by statements executed by it.

sqlr_error is the normal function for signaling a SQL state. It takes a 5 character SQL state, a printf format string and optional arguments, a la printf.

sqlr_resignal is used to throw a condition to the next level handler. This is typically done when executing a query which returns an error and the error is sent up to the caller of the VSE.

srv_make_error makes the error structure. The expression

sqlr_resignal (srv_make_error ("12345", "message")); is equivalent to sqlr_error ("12345", "message");

By convention a NULL pointer indicates no error. sqlr_resignal (NULL) is an error.

The macros:

#define ERR_STATE(err)  (((caddr_t*) err)[1])
#define ERR_MESSAGE(err)  (((caddr_t*) err)[2])

can be used to read an error returned by a statement.