The returned value can be: CL_KERNEL_ARG_TYPE_CONST CL_KERNEL_ARG_TYPE_RESTRICT CL_KERNEL_ARG_TYPE_VOLATILE, a combination of the above enums or CL_KERNEL_ARG_TYPE_NONE NOTE: CL_KERNEL_ARG_TYPE_VOLATILE is returned if the argument is a pointer and the referenced type is declared with the volatile qualifier.