qobjectcleanuphandler.3qt

linux下GUI编程工具qt的在线连接帮助手册

'\" t
.TH QObjectCleanupHandler 3qt "11 October 2001" "Trolltech AS" \" -*- nroff -*-
.\" Copyright 1992-2001 Trolltech AS.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
QObjectCleanupHandler \- Watches the lifetime of multiple QObjects
.PP
\fC#include <qobjectcleanuphandler.h>\fR
.PP
Inherits QObject.
.PP
.SS "Public Members"
.in +1c
.ti -1c
.BI "\fBQObjectCleanupHandler\fR ()"
.br
.ti -1c
.BI "\fB~QObjectCleanupHandler\fR ()"
.br
.ti -1c
.BI "QObject * \fBadd\fR ( QObject * object )"
.br
.ti -1c
.BI "void \fBremove\fR ( QObject * object )"
.br
.ti -1c
.BI "bool \fBisEmpty\fR () const"
.br
.ti -1c
.BI "void \fBclear\fR ()"
.br
.in -1c
.SH DESCRIPTION
The QObjectCleanupHandler class watches the lifetime of multiple QObjects.
.PP
A QObjectCleanupHandler is useful whenever you need to know when a number of QObjects that are owned by someone else has been deleted. This is e.g. important when referencing memory in an application that has been allocated in a shared library.
.PP
Example:
.PP
.nf
.br
  class FactoryComponent : public FactoryInterface, public QLibraryInterface
.br
  {
.br
  public:
.br
     ...
.br
.br
     QObject *createObject();
.br
.br
     bool init();
.br
     void cleanup();
.br
     bool canUnload() const;
.br
.br
  private:
.br
     QObjectCleanupHandler objects;
.br
  };
.br
.br
  // allocate a new object, and add it to the cleanup handler
.br
  QObject *FactoryComponent::createObject()
.br
  {
.br
      return objects.add( new QObject() );
.br
  }
.br
.br
  // QLibraryInterface implementation
.br
  bool FactoryComponent::init()
.br
  {
.br
      return TRUE;
.br
  }
.br
.br
  void FactoryComponent::cleanup()
.br
  {
.br
  }
.br
.br
  // it is only safe to unload the library when all QObject's have been destroyed
.br
  bool FactoryComponent::canUnload() const
.br
  {
.br
      return objects.isEmpty();
.br
  }
.br
.fi
.PP
See also Object Model.
.SH MEMBER FUNCTION DOCUMENTATION
.SH "QObjectCleanupHandler::QObjectCleanupHandler ()"
Constructs an empty QObjectCleanupHandler.
.SH "QObjectCleanupHandler::~QObjectCleanupHandler ()"
Destroys the cleanup handler. All objects in this cleanup handler will be deleted.
.SH "QObject * QObjectCleanupHandler::add ( QObject * object )"
Adds \fIobject\fR to this cleanup handler and returns the pointer to the object.
.SH "void QObjectCleanupHandler::clear ()"
Deletes all objects in this cleanup handler. The cleanup handler becomes empty.
.SH "bool QObjectCleanupHandler::isEmpty () const"
Returns TRUE if this cleanup handler is empty or all objects in this cleanup handler have been destroyed, otherwise return FALSE.
.SH "void QObjectCleanupHandler::remove ( QObject * object )"
Removes the \fIobject\fR from this cleanup handler. The object will not be destroyed.

.SH "SEE ALSO"
.BR http://doc.trolltech.com/qobjectcleanuphandler.html
.BR http://www.trolltech.com/faq/tech.html
.SH COPYRIGHT
Copyright 1992-2001 Trolltech AS, http://www.trolltech.com.  See the
license file included in the distribution for a complete license
statement.
.SH AUTHOR
Generated automatically from the source code.
.SH BUGS
If you find a bug in Qt, please report it as described in
.BR http://doc.trolltech.com/bughowto.html .
Good bug reports help us to help you. Thank you.
.P
The definitive Qt documentation is provided in HTML format; it is
located at $QTDIR/doc/html and can be read using Qt Assistant or with
a web browser. This man page is provided as a convenience for those
users who prefer man pages, although this format is not officially
supported by Trolltech. 
.P
If you find errors in this manual page, please report them to
.BR [e-mail] .
Please include the name of the manual page (qobjectcleanuphandler.3qt) and the Qt
version (3.0.0).