Viadeo Twitter Google Bookmarks ! Facebook Digg del.icio.us MySpace Yahoo MyWeb Blinklist Netvouz Reddit Simpy StumbleUpon Bookmarks Windows Live Favorites 
Logo Documentation Qt ·  Page d'accueil  ·  Toutes les classes  ·  Toutes les fonctions  ·  Vues d'ensemble  · 

QFileSystemWatcher Class Reference

The QFileSystemWatcher class provides an interface for monitoring files and directories for modifications. More...

 #include <QFileSystemWatcher>

Inherits: QObject.

Note: All functions in this class are reentrant.

This class was introduced in Qt 4.2.

Public Functions

QFileSystemWatcher ( QObject * parent = 0 )
QFileSystemWatcher ( const QStringList & paths, QObject * parent = 0 )
~QFileSystemWatcher ()
void addPath ( const QString & path )
void addPaths ( const QStringList & paths )
QStringList directories () const
QStringList files () const
void removePath ( const QString & path )
void removePaths ( const QStringList & paths )
  • 29 public functions inherited from QObject

Signals

void directoryChanged ( const QString & path )
void fileChanged ( const QString & path )

Additional Inherited Members

  • 1 property inherited from QObject
  • 1 public slot inherited from QObject
  • 5 static public members inherited from QObject
  • 7 protected functions inherited from QObject

Detailed Description

The QFileSystemWatcher class provides an interface for monitoring files and directories for modifications.

QFileSystemWatcher monitors the file system for changes to files and directories by watching a list of specified paths.

Call addPath() to watch a particular file or directory. Multiple paths can be added using the addPaths() function. Existing paths can be removed by using the removePath() and removePaths() functions.

QFileSystemWatcher examines each path added to it. Files that have been added to the QFileSystemWatcher can be accessed using the files() function, and directories using the directories() function.

The fileChanged() signal is emitted when a file has been modified, renamed or removed from disk. Similarly, the directoryChanged() signal is emitted when a directory or its contents is modified or removed. Note that QFileSystemWatcher stops monitoring files once they have been renamed or removed from disk, and directories once they have been removed from disk.

Note: On systems running a Linux kernel without inotify support, file systems that contain watched paths cannot be unmounted.

Note: Windows CE does not support directory monitoring by default as this depends on the file system driver installed.

Note: The act of monitoring files and directories for modifications consumes system resources. This implies there is a limit to the number of files and directories your process can monitor simultaneously. On Mac OS X 10.4 and all BSD variants, for example, an open file descriptor is required for each monitored file. Some system limits the number of open file descriptors to 256 by default. This means that addPath() and addPaths() will fail if your process tries to add more than 256 files or directories to the file system monitor. Also note that your process may have other file descriptors open in addition to the ones for files being monitored, and these other open descriptors also count in the total. Mac OS X 10.5 and up use a different backend and do not suffer from this issue.

See also QFile and QDir.

Member Function Documentation

QFileSystemWatcher::QFileSystemWatcher ( QObject * parent = 0 )

Constructs a new file system watcher object with the given parent.

QFileSystemWatcher::QFileSystemWatcher ( const QStringList & paths, QObject * parent = 0 )

Constructs a new file system watcher object with the given parent which monitors the specified paths list.

QFileSystemWatcher::~QFileSystemWatcher ()

Destroys the file system watcher.

Note: To avoid deadlocks on shutdown, all instances of QFileSystemWatcher need to be destroyed before QCoreApplication. Note that passing QCoreApplication::instance() as the parent object when creating QFileSystemWatcher is not sufficient.

void QFileSystemWatcher::addPath ( const QString & path )

Adds path to the file system watcher if path exists. The path is not added if it does not exist, or if it is already being monitored by the file system watcher.

If path specifies a directory, the directoryChanged() signal will be emitted when path is modified or removed from disk; otherwise the fileChanged() signal is emitted when path is modified, renamed or removed.

Note: There is a system dependent limit to the number of files and directories that can be monitored simultaneously. If this limit has been reached, path will not be added to the file system watcher, and a warning message will be printed to stderr.

See also addPaths() and removePath().

void QFileSystemWatcher::addPaths ( const QStringList & paths )

Adds each path in paths to the file system watcher. Paths are not added if they not exist, or if they are already being monitored by the file system watcher.

If a path specifies a directory, the directoryChanged() signal will be emitted when the path is modified or removed from disk; otherwise the fileChanged() signal is emitted when the path is modified, renamed, or removed.

Note: There is a system dependent limit to the number of files and directories that can be monitored simultaneously. If this limit has been reached, the excess paths will not be added to the file system watcher, and a warning message will be printed to stderr for each path that could not be added.

See also addPath() and removePaths().

QStringList QFileSystemWatcher::directories () const

Returns a list of paths to directories that are being watched.

See also files().

void QFileSystemWatcher::directoryChanged ( const QString & path ) [signal]

This signal is emitted when the directory at a specified path, is modified (e.g., when a file is added, modified or deleted) or removed from disk. Note that if there are several changes during a short period of time, some of the changes might not emit this signal. However, the last change in the sequence of changes will always generate this signal.

See also fileChanged().

void QFileSystemWatcher::fileChanged ( const QString & path ) [signal]

This signal is emitted when the file at the specified path is modified, renamed or removed from disk.

See also directoryChanged().

QStringList QFileSystemWatcher::files () const

Returns a list of paths to files that are being watched.

See also directories().

void QFileSystemWatcher::removePath ( const QString & path )

Removes the specified path from the file system watcher.

See also removePaths() and addPath().

void QFileSystemWatcher::removePaths ( const QStringList & paths )

Removes the specified paths from the file system watcher.

See also removePath() and addPaths().

Publicité

Best Of

Actualités les plus lues

Semaine
Mois
Année
  1. « Quelque chose ne va vraiment pas avec les développeurs "modernes" », un développeur à "l'ancienne" critique la multiplication des bibliothèques 59
  2. Apercevoir la troisième dimension ou l'utilisation multithreadée d'OpenGL dans Qt, un article des Qt Quarterly traduit par Guillaume Belz 0
  3. Les développeurs ignorent-ils trop les failles découvertes dans leur code ? Prenez-vous en compte les remarques des autres ? 17
  4. BlackBerry 10 : premières images du prochain OS de RIM qui devrait intégrer des widgets et des tuiles inspirées de Windows Phone 0
  5. Quelles nouveautés de C++11 Visual C++ doit-il rapidement intégrer ? Donnez-nous votre avis 10
  6. Adieu qmake, bienvenue qbs : Qt Building Suite, un outil déclaratif et extensible pour la compilation de projets Qt 17
  7. La rubrique Qt a besoin de vous ! 1
Page suivante

Le Qt Labs au hasard

Logo

Construire l'avenir : (ré-)introduction aux composants de Qt Quick

Les Qt Labs sont les laboratoires des développeurs de Qt, où ils peuvent partager des impressions sur le framework, son utilisation, ce que pourrait être son futur. Lire l'article.

Communauté

Ressources

Liens utiles

Contact

  • Vous souhaitez rejoindre la rédaction ou proposer un tutoriel, une traduction, une question... ? Postez dans le forum Contribuez ou contactez-nous par MP ou par email (voir en bas de page).

Qt dans le magazine

Cette page est une traduction d'une page de la documentation de Qt, écrite par Nokia Corporation and/or its subsidiary(-ies). Les éventuels problèmes résultant d'une mauvaise traduction ne sont pas imputables à Nokia. Qt 4.7
Copyright © 2012 Developpez LLC. Tous droits réservés Developpez LLC. Aucune reproduction, même partielle, ne peut être faite de ce site et de l'ensemble de son contenu : textes, documents et images sans l'autorisation expresse de Developpez LLC. Sinon, vous encourez selon la loi jusqu'à 3 ans de prison et jusqu'à 300 000 E de dommages et intérêts. Cette page est déposée à la SACD.
Vous avez déniché une erreur ? Un bug ? Une redirection cassée ? Ou tout autre problème, quel qu'il soit ? Ou bien vous désirez participer à ce projet de traduction ? N'hésitez pas à nous contacter ou par MP !
 
 
 
 
Partenaires

Hébergement Web