sigc::signal_base Struct Reference

Base class for the sigc::signal# templates. More...

#include <sigc++/signal_base.h>

Inheritance diagram for sigc::signal_base:

Public Types
typedef std::size_t	size_type
Public Types inherited from sigc::trackable
typedef internal::func_destroy_notify	func_destroy_notify

Public Member Functions
	signal_base () noexcept
	signal_base (const signal_base & src) noexcept
	signal_base (signal_base && src)
	~signal_base ()
void	block (bool should_block=true) noexcept
	Sets the blocking state of all slots in the list. More...
bool	blocked () const noexcept
	Returns whether all slots in the list are blocked. More...
void	clear ()
	Empties the list of slots. More...
bool	empty () const noexcept
	Returns whether the list of slots is empty. More...
signal_base &	operator= (const signal_base & src)
signal_base &	operator= (signal_base && src)
size_type	size () const noexcept
	Returns the number of slots in the list. More...
void	unblock () noexcept
	Unsets the blocking state of all slots in the list. More...
Public Member Functions inherited from sigc::trackable
	trackable () noexcept
	trackable (const trackable & src) noexcept
	trackable (trackable && src)
	~trackable ()
void	add_destroy_notify_callback (void *data, func_destroy_notify func) const
	Add a callback that is executed (notified) when the trackable object is detroyed. More...
void	notify_callbacks ()
	Execute and remove all previously installed callbacks. More...
trackable &	operator= (const trackable & src)
trackable &	operator= (trackable && src)
void	remove_destroy_notify_callback (void *data) const
	Remove a callback previously installed with add_destroy_notify_callback(). More...

Protected Types
typedef internal::signal_impl::iterator_type	iterator_type

Protected Member Functions
iterator_type	connect (const slot_base & slot_)
	Adds a slot at the end of the list of slots. More...
iterator_type	connect (slot_base && slot_)
	Adds a slot at the end of the list of slots. More...
iterator_type	erase (iterator_type i)
	Removes the slot at the given position from the list of slots. More...
internal::signal_impl *	impl () const
	Returns the signal_impl object encapsulating the list of slots. More...
iterator_type	insert (iterator_type i, const slot_base & slot_)
	Adds a slot at the given position into the list of slots. More...
iterator_type	insert (iterator_type i, slot_base && slot_)
	Adds a slot at the given position into the list of slots. More...

Protected Attributes
internal::signal_impl *	impl_
	The signal_impl object encapsulating the slot list. More...

Detailed Description

Base class for the sigc::signal# templates.

signal_base integrates most of the interface of the derived sigc::signal# templates. The implementation, however, resides in sigc::internal::signal_impl. A sigc::internal::signal_impl object is dynamically allocated from signal_base when first connecting a slot to the signal. This ensures that empty signals don't waste memory.

sigc::internal::signal_impl is reference-counted. When a sigc::signal# object is copied, the reference count of its sigc::internal::signal_impl object is incremented. Both sigc::signal# objects then refer to the same sigc::internal::signal_impl object.

Deleting the signal during emission, e.g. from one of its slots, may result in memory leaks. This drawback is fixed in version 3 of libsigc++. A workaround is to make a copy of the signal during the emission:

sigc::signal<...> sig2(*p_sig);
p_sig->emit();

This is not very costly. A sigc::signal<> is not much more than a pointer to a sigc::internal::signal_impl instance, which is not copied.

Member Typedef Documentation

iterator_type

typedef internal::signal_impl::iterator_type sigc::signal_base::iterator_type

protected

size_type

typedef std::size_t sigc::signal_base::size_type

Constructor & Destructor Documentation

signal_base() [1/3]

sigc::signal_base::signal_base ( )

noexcept

signal_base() [2/3]

sigc::signal_base::signal_base ( const signal_base &  src )

noexcept

signal_base() [3/3]

sigc::signal_base::signal_base

(

signal_base &&

src

)

~signal_base()

sigc::signal_base::~signal_base

(

)

Member Function Documentation

block()

void sigc::signal_base::block ( bool  should_block = true )

noexcept

Sets the blocking state of all slots in the list.

If should_block is true then the blocking state is set. Subsequent emissions of the signal don't invoke the functors contained in the slots until unblock() or block() with should_block = false is called. sigc::slot_base::block() and sigc::slot_base::unblock() can change the blocking state of individual slots.

Parameters

should_block

Indicates whether the blocking state should be set or unset.

Since libsigc++ 2.4:

blocked()

bool sigc::signal_base::blocked ( ) const

noexcept

Returns whether all slots in the list are blocked.

Returns

true if all slots are blocked or the list is empty.

Since libsigc++ 2.4:

clear()

void sigc::signal_base::clear

(

)

Empties the list of slots.

connect() [1/2]

iterator_type sigc::signal_base::connect ( const slot_base &  slot_ )

protected

Adds a slot at the end of the list of slots.

With connect(), slots can also be added during signal emission. In this case, they won't be executed until the next emission occurs.

Parameters

slot_

The slot to add to the list of slots.

Returns

An iterator pointing to the new slot in the list.

connect() [2/2]

iterator_type sigc::signal_base::connect ( slot_base &&  slot_ )

protected

Adds a slot at the end of the list of slots.

With connect(), slots can also be added during signal emission. In this case, they won't be executed until the next emission occurs.

Parameters

slot_

The slot to add to the list of slots.

Returns

An iterator pointing to the new slot in the list.

Since libsigc++ 2.8:

empty()

bool sigc::signal_base::empty ( ) const

inlinenoexcept

Returns whether the list of slots is empty.

Returns

true if the list of slots is empty.

erase()

iterator_type sigc::signal_base::erase ( iterator_type  i )

protected

Removes the slot at the given position from the list of slots.

Note that this function does not work during signal emission!

Parameters

i	An iterator pointing to the slot to be removed.

Returns

An iterator pointing to the slot in the list after the one removed.

impl()

internal::signal_impl* sigc::signal_base::impl ( ) const

protected

Returns the signal_impl object encapsulating the list of slots.

Returns

The signal_impl object encapsulating the list of slots.

insert() [1/2]

iterator_type sigc::signal_base::insert ( iterator_type  i, const slot_base &  slot_  )

protected

Adds a slot at the given position into the list of slots.

Note that this function does not work during signal emission!

Parameters

i	An iterator indicating the position where slot_ should be inserted.
slot_	The slot to add to the list of slots.

Returns

An iterator pointing to the new slot in the list.

insert() [2/2]

iterator_type sigc::signal_base::insert ( iterator_type  i, slot_base &&  slot_  )

protected

Adds a slot at the given position into the list of slots.

Note that this function does not work during signal emission!

Parameters

i	An iterator indicating the position where slot_ should be inserted.
slot_	The slot to add to the list of slots.

Returns

An iterator pointing to the new slot in the list.

Since libsigc++ 2.8:

operator=() [1/2]

signal_base& sigc::signal_base::operator=

(

const signal_base &

src

)

operator=() [2/2]

signal_base& sigc::signal_base::operator=

(

signal_base &&

src

)

size()

size_type sigc::signal_base::size ( ) const

noexcept

Returns the number of slots in the list.

Returns

The number of slots in the list.

unblock()

void sigc::signal_base::unblock ( )

noexcept

Unsets the blocking state of all slots in the list.

Since libsigc++ 2.4:

Member Data Documentation

impl_

internal::signal_impl* sigc::signal_base::impl_

mutableprotected

The signal_impl object encapsulating the slot list.