问发生qt5错误：：document *document

EN

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <opencv2/opencv.hpp>
#include <QFileDialog>
#include <QMessageBox>
#include <QDesktopServices>
#include <QUrl>
#include <poppler-qt5.h>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    cv::Mat image = cv::imread("/home/googolhkl/사진/IMG_20150925_1.jpg");
    cv::imshow("display",image);

    QString filename;
    Poppler::Document* document = Poppler::Document::load(filename);
    if (!document || document->isLocked()) {
      // ... error message ....
      delete document;
      return;
    }
}