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1/////////////////////////////////////////////////////////////////////////////
2// Name: snglinst.h
e54c96f1 3// Purpose: interface of wxSingleInstanceChecker
23324ae1 4// Author: wxWidgets team
526954c5 5// Licence: wxWindows licence
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6/////////////////////////////////////////////////////////////////////////////
7
8/**
9 @class wxSingleInstanceChecker
7c913512 10
23324ae1 11 wxSingleInstanceChecker class allows to check that only a single instance of a
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12 program is running.
13
14 To do it, you should create an object of this class. As long as this object
15 is alive, calls to wxSingleInstanceChecker::IsAnotherRunning from other
16 processes will return @true.
7c913512 17
23324ae1 18 As the object should have the life span as big as possible, it makes sense to
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19 create it either as a global or in wxApp::OnInit.
20 For example:
7c913512 21
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22 @code
23 bool MyApp::OnInit()
24 {
956b3d92 25 m_checker = new wxSingleInstanceChecker;
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26 if ( m_checker-IsAnotherRunning() )
27 {
28 wxLogError(_("Another program instance is already running, aborting."));
7c913512 29
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30 delete m_checker; // OnExit() won't be called if we return false
31 m_checker = NULL;
7c913512 32
6bfc18d0 33 return false;
23324ae1 34 }
7c913512 35
23324ae1 36 ... more initializations ...
7c913512 37
6bfc18d0 38 return true;
23324ae1 39 }
7c913512 40
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41 int MyApp::OnExit()
42 {
43 delete m_checker;
7c913512 44
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45 return 0;
46 }
47 @endcode
7c913512 48
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49 Note that by default wxSingleInstanceChecker::CreateDefault() is used to
50 create the checker meaning that it will be initialized differently for
51 different users and thus will allow different users to run the application
52 concurrently which is usually the required behaviour. However if only a
53 single instance of a program should be running system-wide, you need to
54 call Create() with a custom name which does @em not include wxGetUserId().
7c913512 55
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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.
7c913512 58
23324ae1 59 @library{wxbase}
3c99e2fd 60 @category{appmanagement}
23324ae1 61*/
7c913512 62class wxSingleInstanceChecker
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63{
64public:
65 /**
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66 Default constructor.
67
68 You may call Create() after using it or directly call
69 IsAnotherRunning() in which case CreateDefault() will be implicitly
70 used.
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71 */
72 wxSingleInstanceChecker();
73
74 /**
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75 Constructor calling Create().
76
77 This constructor does exactly the same thing as Create() but doesn't
78 allow to check for errors.
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79 */
80 wxSingleInstanceChecker(const wxString& name,
81 const wxString& path = wxEmptyString);
82
83 /**
84 Destructor frees the associated resources.
956b3d92 85
e725ba4f 86 Note that it is not virtual, this class is not meant to be used polymorphically.
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87 */
88 ~wxSingleInstanceChecker();
89
90 /**
91 Initialize the object if it had been created using the default constructor.
956b3d92 92
7c913512 93 Note that you can't call Create() more than once, so calling it if the
956b3d92 94 non default ctor had been used is an error.
3c4f71cc 95
7c913512 96 @param name
e725ba4f 97 Must be given and be as unique as possible. It is used as the
4cc4bfaf 98 mutex name under Win32 and the lock file name under Unix.
956b3d92 99 wxApp::GetAppName() and wxGetUserId() are commonly used to construct
e725ba4f 100 this parameter.
7c913512 101 @param path
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102 The path is optional and is ignored under Win32 and used as the
103 directory to create the lock file in under Unix
104 (default is wxGetHomeDir()).
3c4f71cc 105
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106 @return
107 Returns @false if initialization failed, it doesn't mean that
108 another instance is running -- use IsAnotherRunning() to check for
109 it.
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110
111 @note
956b3d92 112 One of possible reasons while Create() may fail on Unix is that the lock
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113 file used for checking already exists but was not created by the user.
114 Therefore applications shouldn't treat failure of this function as fatal
115 condition, because doing so would open them to the possibility of a
116 Denial of Service attack. Instead, they should alert the user about
117 the problem and offer to continue execution without checking if
118 another instance is running.
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119 */
120 bool Create(const wxString& name,
121 const wxString& path = wxEmptyString);
122
123 /**
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124 Calls Create() with default name.
125
126 This method simply calls Create() with a string composed of
127 wxApp::GetAppName() and wxGetUserId().
128
129 Because this method uses wxApp::GetAppName(), it may only be called
130 after the global application was constructed.
131
132 @since 2.9.1
133 */
134 bool CreateDefault();
135
136 /**
137 Returns @true if another copy of this program is already running and
138 @false otherwise.
139
140 Notice that if the object was created using the default constructor
141 Create() hadn't been called before this method, it will call
142 CreateDefault() automatically.
23324ae1 143 */
328f5751 144 bool IsAnotherRunning() const;
23324ae1 145};
e54c96f1 146