fsWatcher=new QFileSystemWatcher(); 会报错怎么回事
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtCore/QFile>
#include <QtCore/QTextStream>
#include <QFileSystemWatcher>
#include <QDir>
MainWindow::MainWindow(QWidget *parent):
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);

changeread();
path1="/home/ma/ma1/";
fsWatcher=new QFileSystemWatcher();

fsWatcher->addPath(path1);
connect(fsWatcher, SIGNAL(directoryChanged(QString)), this, SLOT(changeread()));


}

[root@localhost ]# make
g++ -c -pipe -O2 -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -I/usr/local/Nokia/Qt-4.7.3_static/mkspecs/linux-g++ -I. -I/usr/local/Nokia/Qt-4.7.3_static/include/QtCore -I/usr/local/Nokia/Qt-4.7.3_static/include/QtGui -I/usr/local/Nokia/Qt-4.7.3_static/include -I. -I. -o widget.o widget.cpp
widget.cpp: In constructor ‘Widget::Widget(QWidget*)’:
widget.cpp:71: 错误：‘fsWatcher’ 在此作用域中尚未声明
widget.cpp: In member function ‘virtual void Widget::paintEvent(QPaintEvent*)’:
widget.cpp:187: 警告：将 ‘double’ 作为实参 1 传递给 ‘void QPainter::drawEllipse(int, int, int, int)’
widget.cpp:187: 警告：将 ‘double’ 作为实参 2 传递给 ‘void QPainter::drawEllipse(int, int, int, int)’
make: *** [widget.o] 错误 1
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[解决办法]

引用:

Quote: 引用:

fsWatcher未声明
QFileSystemWatcher fsWatcher;

申明后 QFileSystemWatcher fsWatcher;
执行 fsWatcher=new QFileSystemWatcher(); 会报错

/usr/lib/libstdc++.so.6: version `GLIBCXX_3.4.9' not found (required by ./qt-creator-linux-x86-opensource-2.7.0.bin)
widget.cpp: In constructor ‘Widget::Widget(QWidget*)’:
widget.cpp:71: 附注：在这里第一次需要生成的方法 ‘QFileSystemWatcher& QFileSystemWatcher::operator=(const QFileSystemWatcher&)’
widget.cpp: In member function ‘virtual void Widget::paintEvent(QPaintEvent*)’:
w

大意了，我写错了是定义指针
QFileSystemWatcher *fsWatcher;