Knowing the size of a Variable argument list

[Hamid Mushtaq]

Is there a way to know the size of a variable argument list, without using a sentinel parameter.
For example, I have a function as below: -

void AssignArray(double* array, double first, ...);

and I used it as follows : -
AssignArray(array, 5.0, 6.0, 7.0);
Is there a way to determine that 3 parameters were passed to the function?