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On occasion, applications may need to communicate directly with a display driver. Windows CE provides an escape code mechanism to make this possible. Applications can invoke the ExtEscape function to pass an escape code and optional data to a display driver. ExtEscape, in turn, passes those parameters to the display driver's DrvEscapefunction. DrvEscapeprocesses the escape code, and returns a value to ExtEscape, which then returns the value to the application. DrvEscapeshould do nothing and return 0 for unsupported escape codes.
Windows CE defines the following display driver escape codes
| Escape Code | Value | OS Version(s) | Purpose |
|---|---|---|---|
| QUERYESCSUPPORT | 8 | 2.10 and later | Determines whether a display driver supports a particular escape code. |
| GETVFRAMEPHYSICAL | 6144 | 2.10 and later | Returns the physical memory location of the video frame buffer. |
| GETVFRAMELEN | 6145 | 2.10 and later | Returns the length of the video frame buffer |
| DBGDRIVERSTAT | 6146 | 2.10 and later | Returns display driver statistics. |
| SETPOWERMANAGEMENT | 6147 | 2.10 and later | Requests a particular power management state. |
| GETPOWERMANAGEMENT | 6148 | 2.10 and later | Queries the current power management state. |
| CONTRASTCOMMAND | 6149 | 2.12 and later | Applies a display contrast setting. |
| Reserved | 6150—
99,999 |
Reserved for future use. |
OEMs can define additional driver-specific escape codes, starting at the decimal value 100,000. Microsoft reserves all escape code values up to 99,999. OEMs should note that the sample display drivers for the CEPC and ODO platforms do not implement all of these escape codes.
Last updated on Tuesday, July 13, 2004