ceph/src/boost/libs/signals2/example/disconnect_and_block.cpp

   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 }