File status (see the table below) or empty string if an error occurred. To find out the error number, use MCIErr. To find out the error wording, use function MCIMsgErr or function ErrorInfo with the constant errMessage.
The status report of the command is returned by MCIRetrieve.

MciStatusStop	The file is stopped
MciStatusRecord	The file is currently recorded
MciStatusPlay	The file is opened and it is currently played
MciStatusOpen	File opened only.
MciStatusParked	The player is parked: the player heads parked.
MciStatusNotReady	Drive not ready (no CD in the drive for example)
MciStatusPause	The file is paused
MciStatusSeek	Find/seek in progress in the file

Name of multimedia file to use (AVI, MP3, ...) or alias defined when opening the file (MCIOpen).

Additional parameters if necessary. These parameters can be known by checking the documentation of the Windows MCI function named "status".
The MciWait constant can be added to this string. This constant is used to indicate that the program must wait for the end of the MCI command to run the rest of application.

Name of window used to intercept and manage the different messages sent by MMSYSTEM.DLL. These messages are of type MM_xxxxxx and can be retrieved using function Event. You can for example get messages regarding the management of the CD ROM or Joystick.