Glib::SignalIdle Class Reference
The Main Event Loop

`#include <glibmm/main.h>`

## Public Member Functions

sigc::connection | connect (const sigc::slot< bool >& slot, int priority=PRIORITY_DEFAULT_IDLE)
| Connects an idle handler. More...
void | connect_once (const sigc::slot< void >& slot, int priority=PRIORITY_DEFAULT_IDLE)
| Connects an idle handler that runs only once. More...

## Member Function Documentation

sigc::connection Glib::SignalIdle::connect | ( | const sigc::slot< bool > & | slot,
|  | int | priority = `PRIORITY_DEFAULT_IDLE`
| ) |  |

Connects an idle handler.

bool idle_handler() { ... }
Glib::signal_idle().connect(sigc::ptr_fun(& idle_handler));

is equivalent to:

bool idle_handler() { ... }
const auto idle_source = Glib::IdleSource::create();
idle_source->connect(sigc::ptr_fun(& idle_handler));
idle_source->attach(Glib::MainContext::get_default());

This method is not thread-safe. You should call it, or manipulate the returned sigc::connection object, only from the thread where the SignalIdle object's MainContext runs.

Parameters

  slot | A slot to call when the main loop is idle. If `idle_handler()` returns `false` the handler is disconnected.
  priority | The priority of the new event source.

Returns
  A connection handle, which can be used to disconnect the handler.

void Glib::SignalIdle::connect_once | ( | const sigc::slot< void > & | slot,
|  | int | priority = `PRIORITY_DEFAULT_IDLE`
| ) |  |

Connects an idle handler that runs only once.

This method takes a function pointer to a function with a void return and no parameters. After running once it is not called again.

Because sigc::trackable is not thread-safe, if the slot represents a non-static method of a class deriving from sigc::trackable, and the slot is created by sigc::mem_fun(), connect_once() should only be called from the thread where the SignalIdle object's MainContext runs. You can use, say, boost::bind() or, in C++11, std::bind() or a C++11 lambda expression instead of sigc::mem_fun().

See also
  connect()

Parameters

  slot | A slot to call when the main loop is idle. For example: void on_idle_once()
  priority | The priority of the new event source.

Examples:
  thread/dispatcher.cc.