If the signature of the method is not known at compile time (and hence the method's argument list cannot be constructed until run time), then the method can be invoked at run time by (a) placing the arguments in a variable of type va_list at run time and (b) either using the somGetMethodData method followed by use of the somApply function, or by invoking the somDispatch or somClassDispatch method. Using somApply is more efficient, since this is what the somDispatch method does, but it requires two steps instead of one. In either case, the result invokes a "stub" procedure called an apply stub, whose purpose is to remove the method arguments from the va_list, and then pass them to the appropriate method procedure in the way expected by that procedure. For more information on these methods and for examples of their use, see the somApply function, and the somGetMethodData, somDispatch, and somClassDispatch methods in the System Object Model Programming Reference.