[英]How to use libusb with libevent?
I'm writing an event-driven application using libevent, and I need to do a USB transfer using libusb-1.0.我正在使用 libevent 编写一个事件驱动的应用程序,我需要使用 libusb-1.0 进行 USB 传输。
I wanted to use libusb_get_pollfds to get a list of files descriptors (in fds
) and add them to libevent like this:我想使用libusb_get_pollfds来获取文件描述符列表(在fds
中)并将它们添加到 libevent 中,如下所示:
const struct libusb_pollfd **fds = libusb_get_pollfds(device->context);
const struct libusb_pollfd *it = *fds;
for(;it != NULL; ++it) {
cout << "Adding fd: " << it->fd << ", " << it->events << endl;
struct event * ev = event_new(base_,
it->fd, it->events | EV_PERSIST,
callbacks::libusb_cb, this);
event_add(ev, 0);
libusb_fds_events.insert(std::make_pair(it->fd, ev));
}
free(fds);
// (...)
// And the callback function:
void callbacks::libusb_cb(evutil_socket_t fd, short what, void *arg) {
Server *s = reinterpret_cast<Server*>(arg);
libusb_handle_events_timeout(s->device_->context, 0);
}
Also, I use libusb_set_pollfd_notifiers to add/remove fds from libusb_fds_events
.另外,我使用libusb_set_pollfd_notifiers从libusb_fds_events
添加/删除 fds。
The problem is I get many strange fds on the list returned by libusb (for example, I get stdin
(.) many times with event equals to 0).问题是我在 libusb 返回的列表上得到了许多奇怪的 fds(例如,我得到stdin
(.) 多次,事件等于 0)。
Am I using it in right way?我是否以正确的方式使用它?
I found an error in code.我在代码中发现了一个错误。 It should have been:它应该是:
const struct libusb_pollfd **it = fds;
for(;*it != NULL; ++it) {
cout << "Adding fd: " << (*it)->fd << ", " << (*it)->events << endl;
struct event * ev = event_new(base_,
(*it)->fd, (*it)->events | EV_PERSIST,
callbacks::libusb_cb, this);
event_add(ev, 0);
libusb_fds_events.insert(std::make_pair((*it)->fd, ev));
}
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.