This example shows how to optionally return an error.
// Function: MySqrt
// Returns: LPXLOPER
// Description: Returns the square root of the input
//{{XLP_SRC(MySqrt)
// NOTE - the FunctionWizard will add and remove mapping code here.
// DO NOT EDIT what you see in these blocks of generated code!
IMPLEMENT_XLLFN2(MySqrt, "RB", "MySqrt", "Input", "User Defined",
"Returns the square root of the input", "Number whose square "
"root is to be returned\000", "\0", 1)
extern "C" __declspec( dllexport )
LPXLOPER MySqrt(double dInput)
{
CXlOper xloResult;
//}}XLP_SRC
if ( dInput > 0.0 )
xloResult = sqrt(dInput);
else
xloResult = (WORD)(-dInput);
return xloResult.Ret();
}