This specialization of Switch for a value of 1 of the parameterized t_SWITCH_SELECTOR selects the parameterized t_T1 as Type.
Synopsis
Declared in <bslmf_switch.h>
template<
class t_T0,
class t_T1,
class... t_TYPES>
struct Switch<1U, t_T0, t_T1, t_TYPES...>;