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1 | // Various simple examples involving disconnecting and blocking slots. |
2 | // Copyright Douglas Gregor 2001-2004. | |
3 | // Copyright Frank Mori Hess 2009. | |
4 | // | |
5 | // Use, modification and | |
6 | // distribution is subject to the Boost Software License, Version | |
7 | // 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
8 | // http://www.boost.org/LICENSE_1_0.txt) | |
9 | // For more information, see http://www.boost.org | |
10 | ||
11 | #include <iostream> | |
12 | #include <boost/signals2/signal.hpp> | |
13 | #include <boost/signals2/shared_connection_block.hpp> | |
14 | ||
15 | struct HelloWorld | |
16 | { | |
17 | void operator()() const | |
18 | { | |
19 | std::cout << "Hello, World!" << std::endl; | |
20 | } | |
21 | }; | |
22 | ||
23 | void disconnect_example() | |
24 | { | |
25 | boost::signals2::signal<void ()> sig; | |
26 | ||
27 | //[ disconnect_code_snippet | |
28 | boost::signals2::connection c = sig.connect(HelloWorld()); | |
29 | std::cout << "c is connected\n"; | |
30 | sig(); // Prints "Hello, World!" | |
31 | ||
32 | c.disconnect(); // Disconnect the HelloWorld object | |
33 | std::cout << "c is disconnected\n"; | |
34 | sig(); // Does nothing: there are no connected slots | |
35 | //] | |
36 | } | |
37 | ||
38 | void block_example() | |
39 | { | |
40 | boost::signals2::signal<void ()> sig; | |
41 | ||
42 | //[ block_code_snippet | |
43 | boost::signals2::connection c = sig.connect(HelloWorld()); | |
44 | std::cout << "c is not blocked.\n"; | |
45 | sig(); // Prints "Hello, World!" | |
46 | ||
47 | { | |
48 | boost::signals2::shared_connection_block block(c); // block the slot | |
49 | std::cout << "c is blocked.\n"; | |
50 | sig(); // No output: the slot is blocked | |
51 | } // shared_connection_block going out of scope unblocks the slot | |
52 | std::cout << "c is not blocked.\n"; | |
53 | sig(); // Prints "Hello, World!"} | |
54 | //] | |
55 | } | |
56 | ||
57 | struct ShortLived | |
58 | { | |
59 | void operator()() const | |
60 | { | |
61 | std::cout << "Life is short!" << std::endl; | |
62 | } | |
63 | }; | |
64 | ||
65 | void scoped_connection_example() | |
66 | { | |
67 | boost::signals2::signal<void ()> sig; | |
68 | ||
69 | //[ scoped_connection_code_snippet | |
70 | { | |
71 | boost::signals2::scoped_connection c(sig.connect(ShortLived())); | |
72 | sig(); // will call ShortLived function object | |
73 | } // scoped_connection goes out of scope and disconnects | |
74 | ||
75 | sig(); // ShortLived function object no longer connected to sig | |
76 | //] | |
77 | } | |
78 | ||
79 | //[ disconnect_by_slot_def_code_snippet | |
80 | void foo() { std::cout << "foo"; } | |
81 | void bar() { std::cout << "bar\n"; } | |
82 | //] | |
83 | ||
84 | void disconnect_by_slot_example() | |
85 | { | |
86 | boost::signals2::signal<void()> sig; | |
87 | ||
88 | //[ disconnect_by_slot_usage_code_snippet | |
89 | sig.connect(&foo); | |
90 | sig.connect(&bar); | |
91 | sig(); | |
92 | ||
93 | // disconnects foo, but not bar | |
94 | sig.disconnect(&foo); | |
95 | sig(); | |
96 | //] | |
97 | } | |
98 | ||
99 | int main() | |
100 | { | |
101 | std::cout << "Disconnect example:\n"; | |
102 | disconnect_example(); | |
103 | ||
104 | std::cout << "\nBlock example:\n"; | |
105 | block_example(); | |
106 | ||
107 | std::cout << "\nScoped connection example:\n"; | |
108 | scoped_connection_example(); | |
109 | ||
110 | std::cout << "\nDisconnect by slot example:\n"; | |
111 | disconnect_by_slot_example(); | |
112 | ||
113 | return 0; | |
114 | } |