The mciSendCommand function sends a command message to the specified MCI device.

MCIERROR mciSendCommand(
  UINT        uMsg,       
  DWORD       fdwCommand, 
  DWORD_PTR   dwParam     



Device identifier of the MCI device that is to receive the command message. This parameter is not used with the MCI_OPEN command message.


Command message. For a list, see Multimedia Commands.


Flags for the command message.


Pointer to a structure that contains parameters for the command message.

Return Values

Returns zero if successful or an error otherwise. The low-order word of the returned DWORD value contains the error return value. If the error is device-specific, the high-order word of the return value is the driver identifier; otherwise, the high-order word is zero. For a list of possible return values, see MCIERR Return Values.

To retrieve a text description of mciSendCommand return values, pass the return value to the mciGetErrorString function.


Error values that are returned when a device is being opened are listed with the MCI_OPEN command message. In addition to the MCI_OPEN error return values, this function can return the values listed in MCIERR Return Values.

Use MCI_OPEN to obtain the device identifier specified by the IDDevice parameter.


**  Windows NT/2000/XP:** Included in Windows NT 3.1 and later.
**  Windows 95/98/Me:** Included in Windows 95 and later.
**  Header:** Declared in Mmsystem.h; include Windows.h.
**  Library:** Use Winmm.lib.
**  Unicode:** Implemented as Unicode and ANSI versions on Windows NT/2000/XP.

See Also

MCI, MCI Functions, Command Messages, MCI_OPEN, mciGetErrorString