opencv-imdecode把vector转换成Mat

#include<opencv2/opencv.hpp>
#include<iostream>
#include  <vector>
#include "opencv2/imgcodecs/legacy/constants_c.h" 


int main(int argc, char** argv) {

    FILE* fp;
    errno_t err=fopen_s(&fp, "D:/bb/tu/sansui.jpg", "rb");//以二进制流方式读取图片到内存
    if (err != 0) {
        std::cerr << "cuowu" << std::endl;//提示文件打开错误
    }
    fseek(fp, 0, SEEK_END);
    long lSize = ftell(fp);  //返回指针位置
    rewind(fp);//设置读写指针到文件的开头
    char* pData = new char[lSize];
    fread(pData, sizeof(char), lSize, fp);//读取数据

    fclose(fp);

    cv::Mat img_decode;
    std::vector<uchar> data;

    for (int i = 0; i < lSize; ++i) {
        data.push_back(pData[i]);
    }
    std::cerr << data.size() << std::endl;
    img_decode = cv::imdecode(data, CV_LOAD_IMAGE_COLOR);//把vector转换成Mat
    //需要  #include "opencv2/imgcodecs/legacy/constants_c.h"
    /*
    参数2:
    CV_LOAD_IMAGE_UNCHANGED (<0)，以原始图像读取（包括alpha通道），
    CV_LOAD_IMAGE_GRAYSCALE ( 0)，以灰度图像读取
    CV_LOAD_IMAGE_COLOR (>0)，以BGR格式读取
    */

    std::cerr << lSize << std::endl;

    cv::waitKey(0);
    return 0;
}