# sigc::trackable Struct Reference
[Signals]

Base class for objects with auto-disconnection. More...

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

Inheritance diagram for sigc::trackable:
[legend]

List of all members.

## Public Types
typedef internal::func_destroy_notify | func_destroy_notify
## Public Member Functions
| trackable (const trackable& src)
trackable& | operator= (const trackable& src)
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.
void | remove_destroy_notify_callback (void* data) const
| Remove a callback previously installed with add_destroy_notify_callback().
void | notify_callbacks ()
| Execute and remove all previously installed callbacks.

## Detailed Description

Base class for objects with auto-disconnection.

trackable must be inherited when objects shall automatically invalidate slots referring to them on destruction. A slot built from a member function of a trackable derived type installs a callback that is invoked when the trackable object is destroyed or overwritten.

add_destroy_notify_callback() and remove_destroy_notify_callback() can be used to manually install and remove callbacks when notification of the object dying is needed.

notify_callbacks() invokes and removes all previously installed callbacks and can therefore be used to disconnect from all signals.

Note that there is no virtual destructor. Don't use `trackable*` as pointer type for managing your data or the destructors of your derived types won't be called when deleting your objects.

## Member Function Documentation

void sigc::trackable::add_destroy_notify_callback | ( | void * | data,
|  | func_destroy_notify | func |
| ) |  |  | const

Add a callback that is executed (notified) when the trackable object is detroyed.

Parameters:

  | data | Passed into func upon notification.
  | func | Callback executed upon destruction of the object.

void sigc::trackable::remove_destroy_notify_callback | ( | void * | data | ) | const

Remove a callback previously installed with add_destroy_notify_callback().

The callback is not executed.

Parameters:

  | data | Parameter passed into previous call to add_destroy_notify_callback().