What is the proper way to use inotify?

Question

I want to use the inotify mechanism on Linux. I want my application to know when a file aaa was changed. Can you please provide me with a sample ho

Answer 1

Since the initial question seems to mention Qt as a tag as noted in several comments here, search engines may have lead you here.

If somebody want to know how to do it with Qt, see http://doc.qt.io/qt-5/qfilesystemwatcher.html for the Qt-version. On Linux it uses a subset of Inotify, if it is available, see explanation on the Qt page for details.

Basically the needed code looks like this:

in mainwindow.h add :

QFileSystemWatcher * watcher;
private slots:
    void directoryChanged(const QString & path);
    void fileChanged(const QString & path);

and for mainwindow.cpp:

#include 
#include 

watcher = new QFileSystemWatcher(this);
connect(watcher, SIGNAL(fileChanged(const QString &)), this, SLOT(fileChanged(const QString &)));
connect(watcher, SIGNAL(directoryChanged(const QString &)), this, SLOT(directoryChanged(const QString &)));
watcher->addPath("/tmp/"); // watch directory
watcher->addPath("/tmp/a.file");  // watch file

also add the slots in mainwindow.cpp which are called if a file/directory-change is noticed:

void MainWindow::directoryChanged(const QString & path) {
     qDebug() << path;
}
void MainWindow::fileChanged(const QString & path) {
     qDebug() << path;
}