libsigc++: sigc::connection Struct Reference

libsigc++ 2.12.2

Public Member Functions | Static Public Member Functions | List of all members
sigc::connection Struct Reference
Signals

Convenience class for safe disconnection. More...

`#include <sigc++/connection.h>`

## Public Member Functions
| connection () noexcept
| Constructs an empty connection object.
| connection (const connection & c)
| Constructs a connection object copying an existing one.
template<typename T_slot>
| connection (const slot_iterator< T_slot > & it)
| Constructs a connection object from a slot list iterator.
| connection (slot_base & sl)
| Constructs a connection object from a slot object.
| ~connection ()
bool | block (bool should_block=true) noexcept
| Sets or unsets the blocking state of this connection.
bool | blocked () const noexcept
| Returns whether the connection is blocked.
bool | connected () const noexcept
| Returns whether the connection is still active.
void | disconnect ()
| Disconnects the referred slot.
bool | empty () const noexcept
| Returns whether the connection is still active.
| operator bool () noexcept
| Returns whether the connection is still active.
connection & | operator= (const connection & c)
| Overrides this connection object copying another one.
template<typename T_slot>
connection & | operator= (const slot_iterator< T_slot > & it)
| Overrides this connection object with another slot list iterator.
bool | unblock () noexcept
| Unsets the blocking state of this connection.

## Static Public Member Functions
static void * | notify (void * data)
| Callback that is executed when the referred slot is destroyed.

## Detailed Description

Convenience class for safe disconnection.

sigc::signal::connect() returns a slot list iterator. Iterators must not be used beyond the lifetime of the list they work on. A connection object can be created from a slot list iterator.

sigc::connection conn = sig.connect(sigc::mem_fun(a, & A::foo));
sigc::mem_fun
mem_functor0< T_return, T_obj > mem_fun(T_return(T_obj::*_A_func)())
Creates a functor of type sigc::mem_functor0 which wraps a method.
Definition mem_fun.h:5797
sigc::connection
Convenience class for safe disconnection.
Definition connection.h:41

The connection may safely be used to disconnect the referred slot at any time (disconnect()). If the slot has already been destroyed, disconnect() does nothing. This is possible because the connection object gets notified when the referred slot dies (notify()). empty() or operator bool() can be used to test whether the connection is still active. The connection can be blocked (block(), unblock()).

## Constructor & Destructor Documentation

## ◆ connection() [1/4]

sigc::connection::connection | ( |  | ) |
| noexcept

Constructs an empty connection object.

## ◆ connection() [2/4]

sigc::connection::connection | ( | const connection & | c | ) |

Constructs a connection object copying an existing one.

Parameters

  c | The connection object to make a copy from.

## ◆ connection() [3/4]

template <typename T_slot>

sigc::connection::connection | ( | const slot_iterator< T_slot > & | it | ) |
| inline

Constructs a connection object from a slot list iterator.

Parameters

  it | The slot list iterator to take the slot from.

## ◆ connection() [4/4]

sigc::connection::connection | ( | slot_base & | sl | ) |
| explicit

Constructs a connection object from a slot object.

This is only useful if you create your own slot list.

Parameters

  sl | The slot to operate on.

## ◆ ~connection()

sigc::connection::~connection | ( |  | ) |

## Member Function Documentation

## ◆ block()

bool sigc::connection::block | ( | bool | should_block = true | ) |
| noexcept

Sets or unsets the blocking state of this connection.

See slot_base::block() for details.

Parameters

  should_block | Indicates whether the blocking state should be set or unset.

Returns
  `true` if the connection has been in blocking state before.

## ◆ blocked()

bool sigc::connection::blocked | ( |  | ) | const
| noexcept

Returns whether the connection is blocked.

Returns
  `true` if the connection is blocked.

## ◆ connected()

bool sigc::connection::connected | ( |  | ) | const
| noexcept

Returns whether the connection is still active.

Returns
  `true` if the connection is still active.

## ◆ disconnect()

void sigc::connection::disconnect | ( |  | ) |

Disconnects the referred slot.

## ◆ empty()

bool sigc::connection::empty | ( |  | ) | const
| noexcept

Returns whether the connection is still active.

Returns
  `false` if the connection is still active.

## ◆ notify()

void * sigc::connection::notify | ( | void * | data | ) |
| static

Callback that is executed when the referred slot is destroyed.

Parameters

  data | The connection object notified (`this`).

## ◆ operator bool()

sigc::connection::operator bool | ( |  | ) |
| explicitnoexcept

Returns whether the connection is still active.

Returns
  `true` if the connection is still active.

## ◆ operator=() [1/2]

connection & sigc::connection::operator= | ( | const connection & | c | ) |

Overrides this connection object copying another one.

Parameters

  c | The connection object to make a copy from.

## ◆ operator=() [2/2]

template <typename T_slot>

connection & sigc::connection::operator= | ( | const slot_iterator< T_slot > & | it | ) |
| inline

Overrides this connection object with another slot list iterator.

Parameters

  it | The new slot list iterator to take the slot from.

## ◆ unblock()

bool sigc::connection::unblock | ( |  | ) |
| noexcept

Unsets the blocking state of this connection.

Returns
  `true` if the connection has been in blocking state before.