DrvGetModes

The DrvGetModes function lists the modes supported by a given device.

ULONG
  DrvGetModes(
    IN HANDLE  hDriver,
    IN ULONG  cjSize,
    OUT DEVMODEW  *pdm
    );

Parameters

hDriver

Handle to the driver for which the modes must be enumerated. This is the handle passed in the hDriver parameter of the DrvEnablePDEV function.

cjSize

Specifies the size in bytes of the buffer pointed to by pdm.

pdm

Pointer to the buffer containing DEVMODEW structure(s) for the driver to fill in, or NULL.

Return Value

The driver should return the number of bytes written to the buffer if pdm is not NULL. If pdm is NULL, the driver should return the number of bytes required to hold all mode data. The driver should return zero if an error occurs.

Headers

Declared in winddi.h. Include winddi.h.

Comments

This function must be implemented in all display drivers.

The Window Manager dynamically loads all display drivers associated with a miniport driver (based on the InstalledDisplayDrivers key in the registry). Each display driver is called to retrieve the list of modes supported by that combination of loaded drivers. For example, the VGA64K display driver only returns the 64K color modes that were returned in the list of modes obtained from the miniport driver.

DrvGetModes can be called before there is an active PDEV.

Refer to the permedia samples to see a working implementation of DrvGetModes.

See Also

DEVMODEW, DrvAssertMode, DrvEnablePDEV, EngDeviceIoControl