libusb打开USB设备的示例

以下是libusb打开USB设备的示例：

#include <stdio.h>
#include <stdlib.h>
#include <libusb.h>
 
#define LOGD(...) printf(__VA_ARGS__)
#define LOGE(...) fprintf(stderr, __VA_ARGS__)
 
#define VENDOR_ID 0x04f2   // Example vendor ID
#define PRODUCT_ID 0xb40  // Example product ID
 
static int find_device(libusb_device **dev) {
    libusb_device **devs;
    ssize_t cnt = libusb_get_device_list(NULL, &devs);
    if (cnt < 0) {
        LOGE("Failed to get device list!\n");
        return cnt;
    }
 
    for (ssize_t i = 0; i < cnt; ++i) {
        struct libusb_device_descriptor desc;
        int ret;
 
        ret = libusb_get_device_descriptor(devs[i], &desc);
        if (ret < 0) {
            continue;
        }
        if (desc.idVendor == VENDOR_ID && desc.idProduct == PRODUCT_ID) {
            *dev = devs[i];
            free(devs);
            return 1;
        }
    }
 
    LOGE("No device found!\n");
    free(devs);
    return 0;
}
 
int main() {
    libusb_context *ctx = NULL;
    libusb_device *dev = NULL;
    int ret;
 
    // Initialize libusb
    ret = libusb_init(&ctx);
    if (ret < 0) {
        LOGE("Failed to initialize libusb!\n");
        return EXIT_FAILURE;
    }
 
    ret = find_device(&dev);
    if (ret <= 0) {
        libusb_exit(ctx);
        return EXIT_FAILURE;
    }
 
    libusb_device_handle *handle;
    ret = libusb_open(dev, &handle);
    if (ret < 0) {
        LOGE("Failed to open device!\n");
        libusb_exit(ctx);
        return EXIT_FAILURE;
    }
 
    // Do something with the device here...
 
    libusb_close(handle);
    libusb_exit(ctx);
    return EXIT_SUCCESS;
}