case C_NONE: create_flags = OPEN_EXISTING; break;
case C_CREATE: create_flags = OPEN_ALWAYS; break;
case C_TRUNCATE: create_flags = TRUNCATE_EXISTING; break;
case C_NONE: create_flags = OPEN_EXISTING; break;
case C_CREATE: create_flags = OPEN_ALWAYS; break;
case C_TRUNCATE: create_flags = TRUNCATE_EXISTING; break;