**/
/* iterate for all virtual machines */
- for (s4u::VirtualMachine* ws_vm : VirtualMachineImpl::allVms_) {
+ for (s4u::VirtualMachine* const& ws_vm : VirtualMachineImpl::allVms_) {
surf::Cpu* cpu = ws_vm->pimpl_cpu;
xbt_assert(cpu, "cpu-less host");