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
Size, in
bytes, of the DVTARGETDEVICE structure. The initial size is included so
the structure can be copied more easily.
tdDriverNameOffset
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
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
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
Offset, in
bytes, from the beginning of the structure to the DEVMODE structure
retrieved by calling ExtDeviceMode.
tdData
Aray 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).
Remarks
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 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