28Appendix B - Programming Options
The following example code demonstrates how to obtain Z data. For a complete example, see the included source code for ZAXIS.EXE.
#include "mmioctl.h"
HANDLE hndFile; | // Win32 handle of "MMDev" device | |
LONG | IoctlCode; | // Function to perform |
ULONG | DataLength; | // Output buffer data length |
DWORD | ReturnedLength; | // Actual number of bytes returned |
LONG | IOBuffer; | // Input/output system buffer |
BOOL | IoctlResult; | // Result of operation |
//
// Open Win32 touchscreen device(MMDev)
//
hndFile = CreateFile( "\\\\.\\MMDev",
GENERIC_READ, FILE_SHARE_READ, NULL,
OPEN_EXISTING, 0,
NULL
// Open the device "MMDev"
);
if (hndFile == INVALID_HANDLE_VALUE) {// Was the device opened? MessageBox(NULL, "Unable to open touchscreen",
"Driver Loaded?", MB_OK);
return(0);
}
// See if controller supports Z before going any further
IOBuffer = 0;
IoctlCode = IOCTL_MM_ZAXIS_SUPPORT;
IoctlResult = 0;
DataLength = 4;
IoctlResult = DeviceIoControl(
hndFile, |
| // Handle to device | |
IoctlCode, |
| // IO Control code for | Read |
NULL, |
| // We don't need input | data |
0, |
| // No input buffer required, NULL bytes | |
&IOBuffer, |
| // Buffer from driver. |
|
DataLength, |
| // Length of buffer in | bytes. |
&ReturnedLength, | // Bytes placed in DataBuffer. | ||
NULL |
| // NULL means wait till op. completes. | |
); |
|
|
|
if (!IoctlResult) | // No z |
|
|
MessageBox(NULL, "This controller does not support Z reporting capabilities",
"NO Z", MB_OK MB_ICONEXCLAMATION);
//
//Call the driver to get Z values
IOBuffer = 0;
IoctlResult = 0;
DataLength = sizeof(LONG);
