Automatically Opening a Device

When you issue a command and specify a device that is not open, MCI tries to open the device before implementing the command. The following rules apply to automatically opening devices:

If an application uses the automatic open feature to open a device, the application should check the return value of every subsequent open command to verify that the device is still open. MCI also automatically closes any device that it automatically opens. MCI typically closes a device in the following situations: