libusb 接口已声明

libusb 接口是一个开源的跨平台的通用串行总线接口库，它允许开发人员使用统一的接口与各种USB设备进行通信。libusb 提供了一系列的API函数，使得开发者能够在各种操作系统上轻松地访问和控制USB设备。本文将介绍libusb的基本概念和用法，并通过一个案例代码来演示如何使用libusb进行USB设备的控制。

c
#include 
#include 
#define VENDOR_ID 0x1234
#define PRODUCT_ID 0x5678
#define INTERFACE 0
#define ENDPOINT 0x81
#define BUFFER_SIZE 8
int main() {
    libusb_device_handle *handle;
    unsigned char buffer[BUFFER_SIZE];
    int transferred;
    int ret;
    libusb_init(NULL);
    handle = libusb_open_device_with_vid_pid(NULL, VENDOR_ID, PRODUCT_ID);
    if (handle == NULL) {
        printf("Failed to open USB device.\n");
        return 1;
    }
    ret = libusb_claim_interface(handle, INTERFACE);
    if (ret != 0) {
        printf("Failed to claim USB interface.\n");
        libusb_close(handle);
        return 1;
    }
    buffer[0] = 0x01; // 控制命令，打开灯光
    ret = libusb_bulk_transfer(handle, ENDPOINT, buffer, BUFFER_SIZE, &transferred, 0);
    if (ret != 0) {
        printf("Failed to write data to USB device.\n");
        libusb_release_interface(handle, INTERFACE);
        libusb_close(handle);
        return 1;
    }
    printf("LED light is turned on.\n");
    libusb_release_interface(handle, INTERFACE);
    libusb_close(handle);
    libusb_exit(NULL);
    return 0;
}