update

The update command repaints the current frame into the specified device context (DC). Digital-video devices recognize this command.

To send this command, call the mciSendString function with the lpszCommand parameter set as follows.

_stprintf_s(
  lpszCommand, 
  TEXT("update %s %s %s"), 
  lpszDeviceID, 
  lpszHDC, 
  lpszFlags
); 

Parameters

lpszDeviceID

Identifier of an MCI device. This identifier or alias is assigned when the device is opened.

lpszHDC

Handle of a DC. The following table lists device types that recognize the update command and the flags used by each type.

Value Meaning Meaning
digitalvideo hdc hdc
hdc hdc at rect
paint hdc hdc

The following table lists the flags that can be specified in the lpszHDC parameter and their meanings.

Value Meaning
hdc hdc Specifies the handle of the DC to paint.
hdc hdc at rect Specifies the clipping rectangle relative to the client rectangle.
paint hdc hdc Paints the DC when the application receives a WM_PAINT message intended for a DC.

To specify the handle of the DC, use the string "hdc" followed by an ASCII representation of the handle. The rectangle is specified as X1 Y1 X2 Y2. The coordinates X1 Y1 specify the upper left corner of the rectangle, and the coordinates X2 Y2 specify the width and height.

lpszFlags

Can be "wait", "notify", or both. For digital-video devices, "test" can also be specified. For more information about these flags, see The Wait, Notify, and Test Flags.

Return Values

Returns zero if successful or an error otherwise.

Remarks

The following command updates the entire display window used by the "movie" device. The number 203 is a handle to a DC obtained from the BeginPaint function:

update movie hdc 203

Requirements

  Windows NT/2000/XP: Included in Windows NT 3.1 and later.
  Windows 95/98/Me: Included in Windows 95 and later.

See Also

MCI, MCI Command Strings, BeginPaint, WM_PAINT

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