The array is an array of pointers to pval' s; The pointers are sent as-is to the function, which means if the function modifies its arguments, the original values are changed (passing by reference).
An array of pointers to values that will be passed as arguments to the function, the first argument being in offset 0, the second in offset 1, etc. The array is an array of pointers to pval's; The pointers are sent as-is to the function, which means if the function modifies its arguments, the original values are changed (passing by reference). If you don't want that behavior, pass a copy instead.