DVTARGETDEVICE - OLE Programmer's Reference (ole.hlp)

DVTARGETDEVICE

Use the DVTARGETDEVICE structure to specify information about the target device for which data is being composed. DVTARGETDEVICE contains enough information about a Windows target device so a handle to a device context (hDC) can be created using the Windows CreateDC function.

typedef struct tagDVTARGETDEVICE
{
DWORD tdSize;
WORD tdDriverNameOffset;
WORD tdDeviceNameOffset;
WORD tdPortNameOffset;
WORD tdExtDevmodeOffset;
BYTE tdData[1];
}DVTARGETDEVICE;

Members
tdSize
Specifies the size in bytes of the DVTARGETDEVICE structure. The initial size is included so the structure can be copied more easily.

tdDriverNameOffset
Specifies the offset in bytes from the beginning of the structure to the device driver name, which is stored as a NULL-terminated string in the tdData buffer.

tdDeviceNameOffset
Specifies the offset in bytes from the beginning of the structure to the device name, which is stored as a NULL-terminated string in the tdData buffer. This value can be zero to indicate no device name.

tdPortNameOffset
Specifies the offset in bytes from the beginning of the structure to the port name, which is stored as a NULL-terminated string in the tdData buffer. This value can be zero to indicate no port name.

tdExtDevmodeOffset
Specifies the offset in bytes from the beginning of the structure to the DEVMODE structure retrieved by the calling ExtDeviceMode.

tdData
Specifies an array of bytes containing data for the target device. It is not necessary to include empty strings in tdData (for names where the offset value is zero).

Comments
Some OLE 1 client applications incorrectly construct target devices by allocating too few bytes in the DEVMODE structure for the OLETARGETDEVICE. They typically only supply the number of bytes in the DEVMODE.dmSize member. The number of bytes to be allocated should be the sum of DEVMODE.dmSize + DEVMODE.dmDriverExtra. When a call is made to the CreateDC API function with an incorrect target device, the printer driver tries to access the additional bytes and unpredictable results can occur. To protect against a crash and make the additional bytes available, OLE pads the size of OLE 2 target devices created from OLE 1 target devices.

See Also
FORMATETC, IEnumFORMATETC, IViewObject, OleConvertOLESTREAMToIStorage

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