QT5.14: 打开文件出错warning: format '%s' expects argument of type 'char*'

错误提示信息：

D:\Demo\QT5.14\CH5\CH501\imgprocessor.cpp:158: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'QChar*' [-Wformat=]
printf("file Name:%s\n",filename.data());

原函数代码：

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void ImgProcessor::loadFile(QString filename) {     printf("file Name:%s\n", filename.data());     QFile file(filename);     if(file.open(QIODevice::ReadOnly|QIODevice::Text)){         QTextStream textStream(&file);         while(!textStream.atEnd()){             showWidget->text->append(textStream.readLine());             printf("read line\n");         }         printf("end\n");     } }

　　

修改后，没有提示：

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void ImgProcessor::loadFile(QString filename) {     printf("file Name:%s\n", (char*)filename.data());     QFile file(filename);     if(file.open(QIODevice::ReadOnly|QIODevice::Text)){         QTextStream textStream(&file);         while(!textStream.atEnd()){             showWidget->text->append(textStream.readLine());             printf("read line\n");         }         printf("end\n");     } }

　　主要修改句：

   printf("file Name:%s\n", (char*)filename.data());