Calls an internal Microsoft Excel worksheet function, macro sheet function or command, or XLL-only special function or command, from within a DLL, XLL, or code resource.
All recent versions of Excel support Excel4v. Starting in Excel 2007, Excel12v is supported.
These functions can be called only when Excel has passed control to the DLL or XLL. They can also be called when Excel has passed control indirectly via a call to Visual Basic for Applications (VBA). They cannot be called at any other time. For example, they cannot be called during calls to theDllMainfunction or other times when the operating system has called the DLL, or from a thread created by the DLL.
The Excel4 and Excel12 functions accept their arguments as a variable length list on the stack, whereas the Excel4v and Excel12v functions accept their arguments as an array. In all other respects, Excel4 behaves the same as Excel4v, and Excel12 behaves the same as Excel12v.
A number that indicates the command, function, or special function you want to call. For a list of valid iFunction values, see the following Remarks section.
pxRes (LPXLOPER or LPXLOPER12)
A pointer to an XLOPER (in the case of Excel4v) or an XLOPER12 (in the case of Excel12v) that will hold the result of the evaluated function.
The number of subsequent arguments that will be passed to the function. In versions of Excel up to 2003 this can be any number from 0 through 30. Starting in Excel 2007, this can be any number from 0 through 255.
rgx (LPXLOPER  or LPXLOPER12 )
An array that contains the arguments to the function. All arguments in the array must be pointers to XLOPER or XLOPER12 values.
These functions are useful where the number of arguments passed to the operator is variable. For example, Excel4v and Excel12v are useful when you register functions by using xlfRegister where the number of total arguments depends on the number of arguments taken by the function being registered. Excel4v and Excel12v are also useful when you write a wrapper function for Excel4 or Excel12. In these cases, you need to convert a variable argument list, as would normally be supplied to Excel4 or Excel12, to a single array argument of variable size to call back into Excel by using Excel4v or Excel12v.