xlGetInst
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Returns the instance handle of the instance of Microsoft Office Excel that is currently calling a DLL.
Excel4(xlGetInst, LPXLOPER pxRes, 0); /* returns low part only */
Excel12(xlGetInst, LPXLOPER12 pxRes, 0); /* returns full handle */
Parameters
This function has no arguments.
Property Value/Return Value
The instance handle (xltypeInt) will be in the val.w field.
Remarks
This function can be used to distinguish between multiple running instances of Excel that are calling the DLL.
When you are calling this function using Excel4 or Excel4v, the returned XLOPER integer variable is a signed 16-bit short int. This is only capable of containing the low 16 bits of the 32-bit Windows handle. In Microsoft Office Excel 2007, the integer variable of the XLOPER12 is a signed 32-bit int and therefore contains the entire handle, removing the need to iterate all open windows.
Example
The following example compares the instance of the last copy of Excel that called it to the current copy of Excel that called it. If they are the same, it returns 1; if not, it returns 0.
\SAMPLES\EXAMPLE\EXAMPLE.C
short WINAPI xlGetInstExample(void)
{
XLOPER xRes;
static HANDLE hOld = 0;
int iRet;
Excel4(xlGetInst, (LPXLOPER)&xRes, 0);
if((unsigned int)xRes.val.w != hOld)
iRet = 0;
else
iRet = 1;
hOld = xRes.val.w;
return iRet;
}