OCI And Threading

Question

I have an OCI program running on NT. Things seem to run fine for
a while, however, if I have multiple clients or one client with
multiple threads, a situation occurs where although
client/thread 'A' has a row locked (via a select for update in a
stored procedure), client/thread 'B' can occassionally lock the
row!!! At first I thought it may be due to client/thread 'B'
caching information, so I tried completely
disconnecting/connecting to the database between calls... and
its still happening. What would cause a connection to release
it's locks, other than a commit/rollback?

Answer 1

All you need to do is out-bind a char buffer and integer status to a call to a PL/SQL statement that calls dbms_output.get_line(). When status == 0, there is a line in the buffer:
char buffer[32767];
int status = 0;
sb2 indp = OCI_IND_NULL;
char *sql =   "BEGIN DBMS_OUTPUT.GET_LINE(line=>:p1, status=>:p2); END;";
OCIHandleAlloc(envhp, (dvoid **)&sth, (ub4)OCI_HTYPE_STMT, (size_t)0, (dvoid **)0);
OCIStmtPrepare2 (svc, &sth, errhp, sql, strlen(sql), 0, 0, OCI_NTV_SYNTAX, OCI_DEFAULT);
OCIBindByPos(sth, &bhp1, errhp, 1, (dvoid *)value, sizeof(value)+1, SQLT_STR, &indp, 0, 0, 0, 0, OCI_DEFAULT);
OCIBindByPos(sth, &bhp2, errhp, 2, (dvoid *)&status, sizeof(status), SQLT_INT, &indp, 0, 0, 0, 0, OCI_DEFAULT);
ret = OCIStmtExecute(svc, sth, errhp, (ub4)1, 0, NULL, NULL, OCI_DEFAULT);
while( OCI_SUCCESS==ret && 1 != status ) {
printf("%s\n", buffer);
}