Function instr_set_num_opnds 

pub unsafe extern "C" fn instr_set_num_opnds(
    drcontext: *mut c_void,
    instr: *mut instr_t,
    num_dsts: c_int,
    num_srcs: c_int,
)

Assumes that \p instr has been initialized but does not have any operands yet. Allocates storage for \p num_srcs source operands and \p num_dsts destination operands.