30 struct Serial {  struct
31     std::string_view serial;  member
34 using DeviceSelection = std::variant<std::monostate, AllDevices, SingleDevice, Serial>;  argument
37     fprintf(stderr, "usage: [ANDROID_SERIAL=SERIAL] usbreset [-d] [-s SERIAL]\n");  in Usage()
40     fprintf(stderr, "\t-s --serial\t\tReset device with specified serial\n");  in Usage()
69     std::variant<std::monostate, AllDevices, SingleDevice, Serial> selection;  in main()
72             {"all", 0, 0, 'a'},    {"help", 0, 0, 'h'}, {"serial", required_argument, 0, 's'},  in main()
83             SetOption(&selection, Serial{optarg});  in main()
85             SetOption(&selection, Serial{optarg});  in main()
94             SetOption(&selection, Serial{env});  in main()
153                 PrintLibusbError(rc, "warning: failed to get device serial");  in main()
157             std::string serial(buf, buf + rc);  in main()  local
158             if (auto s = std::get_if<Serial>(&selection)) {  in main()
159                 if (s->serial == serial) {  in main()
160                     selected_devices.push_back(std::make_pair(std::move(serial), device_handle));  in main()
163                 selected_devices.push_back(std::make_pair(std::move(serial), device_handle));  in main()
175     for (auto& [serial, device_handle] : selected_devices) {  in main()
180             printf("%s: successfully reset\n", serial.c_str());  in main()
182             PrintLibusbError(rc, "%s: failed to reset", serial.c_str());  in main()