ExtEscape
The ExtEscape
function allows applications to access capabilities of a particular device that
are not available through GDI.
int ExtEscape(
|
HDC hdc, |
// handle to device
context |
|
int nEscape, |
// escape function |
|
int cbInput, |
// number of bytes
in input structure |
|
LPCSTR lpszInData, |
// pointer to input
structure |
|
int cbOutput, |
// number of bytes
in output structure |
|
LPSTR lpszOutData |
// pointer to
output structure |
|
); |
|
Parameters
hdc
Identifies
the device context.
nEscape
Specifies the
escape function to be performed.
cbInput
Specifies the
number of bytes of data pointed to by the lpszInData parameter.
lpszInData
Points to the
input structure required for the specified escape.
cbOutput
Specifies the
number of bytes of data pointed to by the lpszOutData parameter.
lpszOutData
Points to the
structure that receives output from this escape. This parameter must not be
NULL if ExtEscape is called as a query function. If no data is to be returned
in this structure, set cbOutput to 0.
Return Values
The return
value specifies the outcome of the function. It is greater than zero if the
function is successful, except for the QUERYESCSUPPORT printer escape, which
checks for implementation only. The return value is zero if the escape is not
implemented. A return value less than zero indicates an error. To get extended
error information, call GetLastError.
Remarks
Use this
function to pass a driver-defined escape value to a device.
Use the Escape
function to pass one of the escape values defined by Windows to a device. ExtEscape
might not work properly with the escapes defined by Windows. In particular,
escapes in which lpszInData points to a structure that contains a member
that is a pointer will fail.
See Also