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Commit	Line	Data
	1	/////////////////////////////////////////////////////////////////////////////
	2	// Name: snglinst.h
	3	// Purpose: interface of wxSingleInstanceChecker
	4	// Author: wxWidgets team
	5	// RCS-ID: $Id$
	6	// Licence: wxWindows license
	7	/////////////////////////////////////////////////////////////////////////////
	8
	9	/**
	10	@class wxSingleInstanceChecker
	11
	12	wxSingleInstanceChecker class allows to check that only a single instance of a
	13	program is running.
	14
	15	To do it, you should create an object of this class. As long as this object
	16	is alive, calls to wxSingleInstanceChecker::IsAnotherRunning from other
	17	processes will return @true.
	18
	19	As the object should have the life span as big as possible, it makes sense to
	20	create it either as a global or in wxApp::OnInit.
	21	For example:
	22
	23	@code
	24	bool MyApp::OnInit()
	25	{
	26	const wxString name = wxString::Format("MyApp-%s", wxGetUserId().c_str());
	27	m_checker = new wxSingleInstanceChecker(name);
	28	if ( m_checker-IsAnotherRunning() )
	29	{
	30	wxLogError(_("Another program instance is already running, aborting."));
	31
	32	delete m_checker; // OnExit() won't be called if we return false
	33	m_checker = NULL;
	34
	35	return false;
	36	}
	37
	38	... more initializations ...
	39
	40	return true;
	41	}
	42
	43	int MyApp::OnExit()
	44	{
	45	delete m_checker;
	46
	47	return 0;
	48	}
	49	@endcode
	50
	51	Note using wxGetUserId() to construct the name: this allows different user
	52	to run the application concurrently which is usually the intended goal.
	53	If you don't use the user name in the wxSingleInstanceChecker name, only
	54	one user would be able to run the application at a time.
	55
	56	This class is implemented for Win32 and Unix platforms (supporting @c fcntl()
	57	system call, but almost all of modern Unix systems do) only.
	58
	59	@library{wxbase}
	60	@category{misc}
	61	*/
	62	class wxSingleInstanceChecker
	63	{
	64	public:
	65	/**
	66	Default ctor, use Create() after it.
	67	*/
	68	wxSingleInstanceChecker();
	69
	70	/**
	71	Like Create() but without error checking.
	72	*/
	73	wxSingleInstanceChecker(const wxString& name,
	74	const wxString& path = wxEmptyString);
	75
	76	/**
	77	Destructor frees the associated resources.
	78	Note that it is not virtual, this class is not meant to be used polymorphically.
	79	*/
	80	~wxSingleInstanceChecker();
	81
	82	/**
	83	Initialize the object if it had been created using the default constructor.
	84	Note that you can't call Create() more than once, so calling it if the
	85	@ref wxSingleInstanceChecker() "non default ctor" had been used is an error.
	86
	87	@param name
	88	Must be given and be as unique as possible. It is used as the
	89	mutex name under Win32 and the lock file name under Unix.
	90	GetAppName() and wxGetUserId() are commonly used to construct
	91	this parameter.
	92	@param path
	93	The path is optional and is ignored under Win32 and used as the
	94	directory to create the lock file in under Unix
	95	(default is wxGetHomeDir()).
	96
	97	@return Returns @false if initialization failed, it doesn't mean that
	98	another instance is running - use IsAnotherRunning() to check
	99	for it.
	100
	101	@note
	102	One of possible reasons while Create may fail on Unix is that the lock
	103	file used for checking already exists but was not created by the user.
	104	Therefore applications shouldn't treat failure of this function as fatal
	105	condition, because doing so would open them to the possibility of a
	106	Denial of Service attack. Instead, they should alert the user about
	107	the problem and offer to continue execution without checking if
	108	another instance is running.
	109	*/
	110	bool Create(const wxString& name,
	111	const wxString& path = wxEmptyString);
	112
	113	/**
	114	Returns @true if another copy of this program is already running, @false
	115	otherwise.
	116	*/
	117	bool IsAnotherRunning() const;
	118	};
	119