C++应用之libusb-(5)libusb热插拔事件

#include 
#include 

#include "libusb.h"

int done = 0;
libusb_device_handle *handle = NULL;

static int LIBUSB_CALL hotplug_callback(libusb_context *ctx, libusb_device *dev, libusb_hotplug_event event, void *user_data)
{
	struct libusb_device_descriptor desc;
	int rc;

	(void)ctx;
	(void)dev;
	(void)event;
	(void)user_data;

	rc = libusb_get_device_descriptor(dev, &desc);
	if (LIBUSB_SUCCESS != rc) {
		fprintf (stderr, "Error getting device descriptor\n");
	}

	printf ("Device attached: %04x:%04x\n", desc.idVendor, desc.idProduct);

	if (handle) {
		libusb_close (handle);
		handle = NULL;
	}

	rc = libusb_open (dev, &handle);
	if (LIBUSB_SUCCESS != rc) {
		fprintf (stderr, "Error opening device\n");
	}

	done++;

	return 0;
}

static int LIBUSB_CALL hotplug_callback_detach(libusb_context *ctx, libusb_device *dev, libusb_hotplug_event event, void *user_data)
{
	(void)ctx;
	(void)dev;
	(void)event;
	(void)user_data;

	printf ("Device detached\n");

	if (handle) {
		libusb_close (handle);
		handle = NULL;
	}

	done++;

	return 0;
}

int main(int argc, char *argv[])
{
	libusb_hotplug_callback_handle hp[2];
	int product_id, vendor_id, class_id;
	int rc;

	vendor_id  = (argc > 1) ? (int)strtol (argv[1], NULL, 0) : 0x045a;
	product_id = (argc > 2) ? (int)strtol (argv[2], NULL, 0) : 0x5005;
	class_id   = (argc > 3) ? (int)strtol (argv[3], NULL, 0) : LIBUSB_HOTPLUG_MATCH_ANY;

	rc = libusb_init (NULL);
	if (rc < 0)
	{
		printf("failed to initialise libusb: %s\n", libusb_error_name(rc));
		return EXIT_FAILURE;
	}

	if (!libusb_has_capability (LIBUSB_CAP_HAS_HOTPLUG)) {
		printf ("Hotplug capabilites are not supported on this platform\n");
		libusb_exit (NULL);
		return EXIT_FAILURE;
	}

	rc = libusb_hotplug_register_callback (NULL, LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED, 0, vendor_id,
		product_id, class_id, hotplug_callback, NULL, &hp[0]);
	if (LIBUSB_SUCCESS != rc) {
		fprintf (stderr, "Error registering callback 0\n");
		libusb_exit (NULL);
		return EXIT_FAILURE;
	}

	rc = libusb_hotplug_register_callback (NULL, LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT, 0, vendor_id,
		product_id,class_id, hotplug_callback_detach, NULL, &hp[1]);
	if (LIBUSB_SUCCESS != rc) {
		fprintf (stderr, "Error registering callback 1\n");
		libusb_exit (NULL);
		return EXIT_FAILURE;
	}

	while (done < 2) {
		rc = libusb_handle_events (NULL);
		if (rc < 0)
			printf("libusb_handle_events() failed: %s\n", libusb_error_name(rc));
	}

	if (handle) {
		libusb_close (handle);
	}

	libusb_exit (NULL);

	return EXIT_SUCCESS;
}

\libusb-1.0.22\Win32\Debug\examples>hotplugtest.exe
Hotplug capabilites are not supported on this platform