Class connection

boost::signals2::connection — Query/disconnect a signal-slot connection.

Synopsis

// In header: <boost/signals2/connection.hpp>


class connection {
public:
  // construct/copy/destruct
  connection();
  connection(const connection&);
  connection& operator=(const connection&);

  // connection management
  void disconnect() const;
  bool connected() const;

  // blocking
  bool blocked() const;

  // modifiers
  void swap(const connection&);

  // comparisons
  bool operator==(const connection&) const;
  bool operator!=(const connection&) const;
  bool operator<(const connection&) const;
};

// specialized algorithms
void swap(connection&, connection&);

Description

The signals2::connection class represents a connection between a Signal and a Slot. It is a lightweight object that has the ability to query whether the signal and slot are currently connected, and to disconnect the signal and slot. It is always safe to query or disconnect a connection.

Thread Safety

The methods of the connection class are thread-safe with the exception of swap and the assignment operator. A connection object should not be accessed concurrently when either of these operations is in progress. However, it is always safe to access a different connection object in another thread, even if the two connection objects are copies of each other which refer to the same underlying connection.

`connection` public construct/copy/destruct

```
connection();
```
Effects:

Sets the currently represented connection to the NULL connection.

Postconditions:

!this->connected().

Throws:

Will not throw.
```
connection(const connection& other);
```
Effects:

this references the connection referenced by other.

Throws:

Will not throw.
```
connection& operator=(const connection& other);
```
Effects:

this references the connection referenced by other.

Throws:

Will not throw.

`connection` connection management

void disconnect() const;

Effects:	If `this->connected()`, disconnects the signal and slot referenced by this; otherwise, this operation is a no-op.
Postconditions:	`!this->connected()`.

```
bool connected() const;
```
Returns:

true if this references a non-NULL connection that is still active (connected), and false otherwise.

Throws:

Will not throw.

`connection` blocking

```
bool blocked() const;
```
Queries if the connection is blocked. A connection may be blocked by creating a boost::signals2::shared_connection_block object.

Returns:

true if the associated slot is either disconnected or blocked, false otherwise.

Throws:

Will not throw.

`connection` modifiers

```
void swap(const connection& other);
```
Effects:

Swaps the connections referenced in this and other.

Throws:

Will not throw.

`connection` comparisons

bool operator==(const connection& other) const;

Returns:	`true` if `this` and `other` reference the same connection or both reference the NULL connection, and `false` otherwise.
Throws:	Will not throw.

bool operator!=(const connection& other) const;

Returns:	`!(*this == other)`
Throws:	Will not throw.

bool operator<(const connection& other) const;

Returns:	`true` if the connection referenced by `this` precedes the connection referenced by `other` based on some unspecified ordering, and `false` otherwise.
Throws:	Will not throw.

`connection` specialized algorithms

void swap(connection& x, connection& y);

Effects:	`x.swap(y)`
Throws:	Will not throw.

Effects:	Sets the currently represented connection to the NULL connection.
Postconditions:	`!this->connected()`.
Throws:	Will not throw.

Effects:	`this` references the connection referenced by `other`.
Throws:	Will not throw.

Returns:	`true` if this references a non-NULL connection that is still active (connected), and `false` otherwise.
Throws:	Will not throw.

Returns:	`true` if the associated slot is either disconnected or blocked, `false` otherwise.
Throws:	Will not throw.

Effects:	Swaps the connections referenced in `this` and `other`.
Throws:	Will not throw.