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Commit	Line	Data
	1	/////////////////////////////////////////////////////////////////////////////
	2	// Name: recguard.h
	3	// Purpose: interface of wxRecursionGuardFlag
	4	// Author: wxWidgets team
	5	// Licence: wxWindows licence
	6	/////////////////////////////////////////////////////////////////////////////
	7
	8	/**
	9	@class wxRecursionGuardFlag
	10
	11	This is a completely opaque class which exists only to be used with
	12	wxRecursionGuard, please see the example in that class' documentation.
	13
	14	@remarks
	15
	16	wxRecursionGuardFlag object must be declared @c static or the recursion
	17	would never be detected.
	18
	19	@library{wxbase}
	20	@category{misc}
	21	*/
	22	class wxRecursionGuardFlag
	23	{
	24	public:
	25
	26	};
	27
	28
	29
	30	/**
	31	@class wxRecursionGuard
	32
	33	wxRecursionGuard is a very simple class which can be used to prevent reentrancy
	34	problems in a function. It is not thread-safe and so should be used only in
	35	single-threaded programs or in combination with some thread synchronization
	36	mechanisms.
	37
	38	wxRecursionGuard is always used together with the
	39	wxRecursionGuardFlag like in this example:
	40
	41	@code
	42	void Foo()
	43	{
	44	static wxRecursionGuardFlag s_flag;
	45	wxRecursionGuard guard(s_flag);
	46	if ( guard.IsInside() )
	47	{
	48	// don't allow reentrancy
	49	return;
	50	}
	51
	52	...
	53	}
	54	@endcode
	55
	56	As you can see, wxRecursionGuard simply tests the flag value and sets it to
	57	@true if it hadn't been already set.
	58	IsInside() allows testing the old flag
	59	value. The advantage of using this class compared to directly manipulating the
	60	flag is that the flag is always reset in the wxRecursionGuard destructor and so
	61	you don't risk to forget to do it even if the function returns in an unexpected
	62	way (for example because an exception has been thrown).
	63
	64	@library{wxbase}
	65	@category{misc}
	66	*/
	67	class wxRecursionGuard
	68	{
	69	public:
	70	/**
	71	A wxRecursionGuard object must always be initialized with a @c static
	72	wxRecursionGuardFlag. The constructor saves the
	73	value of the flag to be able to return the correct value from
	74	IsInside().
	75	*/
	76	wxRecursionGuard(wxRecursionGuardFlag& flag);
	77
	78	/**
	79	The destructor resets the flag value so that the function can be entered again
	80	the next time.
	81
	82	@note This is not virtual, so this class is not meant to be derived
	83	from (besides, there is absolutely no reason to do it anyhow).
	84	*/
	85	~wxRecursionGuard();
	86
	87	/**
	88	Returns @true if we're already inside the code block "protected" by this
	89	wxRecursionGuard (i.e. between this line and the end of current scope).
	90	Usually the function using wxRecursionGuard takes some specific actions
	91	in such case (may be simply returning) to prevent reentrant calls to itself.
	92
	93	If this method returns @false, it is safe to continue.
	94	*/
	95	bool IsInside() const;
	96	};
	97