错误:无效使用非静态成员函数"int test::hotplug_callback(libusb_contex

我改编了libusb热插拔的例子

* libusb example program for hotplug API * Copyright © 2012-2013 Nathan Hjelm <hjelmn@mac.com>

(下面的代码(作为测试并将其放在一个类中，因为我的真实程序也有同样的问题。 我知道如果我把静态放在两个回调前面，它就可以工作，但我不希望它们是静态的。我想从回调访问我的实例变量。这个想法是用户插入一个USB设备，我们称之为usbXYZ。从回调中，我实例化类usbXYZ并放入一个std：：map - 用户删除它，我将其从映射中删除。包含 std：：map 的类及其中的对象具有写入设备的"更高级别"方法。

我如何使回调函数工作无静态？如果可能的话，请解释一下，因为我不明白。谢谢。

#include <stdlib.h>
#include <stdio.h>
#include <thread>
#include "libusb-1.0/libusb.h"
class test{
public:
test() {
okGo();
}
private:
int done = 0;
libusb_device_handle *handle = NULL;
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 descriptorn");
}
printf ("Device attached: %04x:%04xn", desc.idVendor, desc.idProduct);
if (handle) {
libusb_close (handle);
handle = NULL;
}
rc = libusb_open (dev, &handle);
if (LIBUSB_SUCCESS != rc) {
fprintf (stderr, "Error opening devicen");
}
done++;
return 0;
}
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 detachedn");
if (handle) {
libusb_close (handle);
handle = NULL;
}
done++;
return 0;
}
int okGo(){
libusb_hotplug_callback_handle hp[2];
int product_id, vendor_id, class_id;
int rc;
vendor_id  = LIBUSB_HOTPLUG_MATCH_ANY;
product_id = LIBUSB_HOTPLUG_MATCH_ANY;
class_id   = LIBUSB_HOTPLUG_MATCH_ANY;
rc = libusb_init (NULL);
if (rc < 0)
{
printf("failed to initialise libusb: %sn", libusb_error_name(rc));
return EXIT_FAILURE;
}
if (!libusb_has_capability (LIBUSB_CAP_HAS_HOTPLUG)) {
printf ("Hotplug capabilites are not supported on this platformn");
libusb_exit (NULL);
return EXIT_FAILURE;
}
rc = libusb_hotplug_register_callback (NULL, LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED, LIBUSB_HOTPLUG_ENUMERATE, vendor_id,
product_id, class_id, hotplug_callback, NULL, &hp[0]);
if (LIBUSB_SUCCESS != rc) {
fprintf (stderr, "Error registering callback 0n");
libusb_exit (NULL);
return EXIT_FAILURE;
}
rc = libusb_hotplug_register_callback (NULL, LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT, LIBUSB_HOTPLUG_ENUMERATE, vendor_id,
product_id,class_id, hotplug_callback_detach, NULL, &hp[1]);
if (LIBUSB_SUCCESS != rc) {
fprintf (stderr, "Error registering callback 1n");
libusb_exit (NULL);
return EXIT_FAILURE;
}
while (done < 20) {
//rc = libusb_handle_events (NULL);
if (libusb_handle_events_completed(nullptr, nullptr) != LIBUSB_SUCCESS)
printf("libusb_handle_events() failed: %sn", libusb_error_name(rc));
}
if (handle) {
libusb_close (handle);
}
libusb_exit (NULL);
return EXIT_SUCCESS;
}
};

int main(int argc, char *argv[])
{
std::unique_ptr<test> testClass1 = std::make_unique<test>();
//just test
for (;;)
{
//main service loop
std::this_thread::sleep_for(std::chrono::microseconds(2000000));
}
}