X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/6bfc18d01649c47eb2157f1333d8c189be83ee4d..7344108e8a129a3f9b4df5ab0f98a1713db03b89:/interface/wx/snglinst.h diff --git a/interface/wx/snglinst.h b/interface/wx/snglinst.h index 41e539fde2..2d68cd0e00 100644 --- a/interface/wx/snglinst.h +++ b/interface/wx/snglinst.h @@ -3,27 +3,27 @@ // Purpose: interface of wxSingleInstanceChecker // Author: wxWidgets team // RCS-ID: $Id$ -// Licence: wxWindows license +// Licence: wxWindows licence ///////////////////////////////////////////////////////////////////////////// /** @class wxSingleInstanceChecker wxSingleInstanceChecker class allows to check that only a single instance of a - program is running. To do it, you should create an object of this class. As - long as this object is alive, calls to - wxSingleInstanceChecker::IsAnotherRunning from - other processes will return @true. + program is running. + + To do it, you should create an object of this class. As long as this object + is alive, calls to wxSingleInstanceChecker::IsAnotherRunning from other + processes will return @true. As the object should have the life span as big as possible, it makes sense to - create it either as a global or in wxApp::OnInit. For - example: + create it either as a global or in wxApp::OnInit. + For example: @code bool MyApp::OnInit() { - const wxString name = wxString::Format("MyApp-%s", wxGetUserId().c_str()); - m_checker = new wxSingleInstanceChecker(name); + m_checker = new wxSingleInstanceChecker; if ( m_checker-IsAnotherRunning() ) { wxLogError(_("Another program instance is already running, aborting.")); @@ -47,59 +47,100 @@ } @endcode - Note using wxGetUserId() to construct the name: this - allows different user to run the application concurrently which is usually the - intended goal. If you don't use the user name in the wxSingleInstanceChecker - name, only one user would be able to run the application at a time. + Note that by default wxSingleInstanceChecker::CreateDefault() is used to + create the checker meaning that it will be initialized differently for + different users and thus will allow different users to run the application + concurrently which is usually the required behaviour. However if only a + single instance of a program should be running system-wide, you need to + call Create() with a custom name which does @em not include wxGetUserId(). This class is implemented for Win32 and Unix platforms (supporting @c fcntl() system call, but almost all of modern Unix systems do) only. @library{wxbase} - @category{misc} + @category{appmanagement} */ class wxSingleInstanceChecker { public: /** - Like Create() but without - error checking. + Default constructor. + + You may call Create() after using it or directly call + IsAnotherRunning() in which case CreateDefault() will be implicitly + used. + */ + wxSingleInstanceChecker(); + + /** + Constructor calling Create(). + + This constructor does exactly the same thing as Create() but doesn't + allow to check for errors. */ wxSingleInstanceChecker(const wxString& name, const wxString& path = wxEmptyString); /** Destructor frees the associated resources. - Note that it is not virtual, this class is not meant to be used polymorphically + + Note that it is not virtual, this class is not meant to be used polymorphically. */ ~wxSingleInstanceChecker(); /** Initialize the object if it had been created using the default constructor. + Note that you can't call Create() more than once, so calling it if the - @ref wxsingleinstancechecker() "non default ctor" - had been used is an error. + non default ctor had been used is an error. @param name - must be given and be as unique as possible. It is used as the + Must be given and be as unique as possible. It is used as the mutex name under Win32 and the lock file name under Unix. - GetAppName() and wxGetUserId() - are commonly used to construct this parameter. + wxApp::GetAppName() and wxGetUserId() are commonly used to construct + this parameter. @param path - is optional and is ignored under Win32 and used as the directory to - create the lock file in under Unix (default is - wxGetHomeDir()) - - @return Returns @false if initialization failed, it doesn't mean that - another instance is running - use IsAnotherRunning() - to check for it. + The path is optional and is ignored under Win32 and used as the + directory to create the lock file in under Unix + (default is wxGetHomeDir()). + + @return + Returns @false if initialization failed, it doesn't mean that + another instance is running -- use IsAnotherRunning() to check for + it. + + @note + One of possible reasons while Create() may fail on Unix is that the lock + file used for checking already exists but was not created by the user. + Therefore applications shouldn't treat failure of this function as fatal + condition, because doing so would open them to the possibility of a + Denial of Service attack. Instead, they should alert the user about + the problem and offer to continue execution without checking if + another instance is running. */ bool Create(const wxString& name, const wxString& path = wxEmptyString); /** - Returns @true if another copy of this program is already running, @false - otherwise. + Calls Create() with default name. + + This method simply calls Create() with a string composed of + wxApp::GetAppName() and wxGetUserId(). + + Because this method uses wxApp::GetAppName(), it may only be called + after the global application was constructed. + + @since 2.9.1 + */ + bool CreateDefault(); + + /** + Returns @true if another copy of this program is already running and + @false otherwise. + + Notice that if the object was created using the default constructor + Create() hadn't been called before this method, it will call + CreateDefault() automatically. */ bool IsAnotherRunning() const; };