last_value
<R>
int
std::less
<Group>
functionN
<R, T1, T2, ..., TN>
signals::trackable
`noncopyable` Exposition only
Set of safe multicast callback types.

The class template `signalN` covers several related classes signal0, signal1, signal2, etc., where the number suffix describes the number of function parameters the signal and its connected slots will take. Instead of enumerating all classes, a single pattern `signalN` will be described, where N represents the number of function parameters.

typename Combiner::result_type
Combiner
Group
GroupCompare
SlotFunction
`slot`<SlotFunction>
unspecified
unspecified
T1 If N == 1
T1 If N == 2
T2 If N == 2
T1
T2
TN
int N
const combiner_type&
combiner_type()
const group_compare_type&
group_compare_type()

Initializes the signal to contain no slots, copies the given combiner into internal storage, and stores the given group comparison function object to compare groups.

`this->`empty`()`

Disconnects all slots connected to `*this`.

`signals::connection` `const slot_type&` `signals::connect_position signals::at_back`
`signals::connection` `const group_type&` `const slot_type&` `signals::connect_position signals::at_back`

Connects the signal this to the incoming slot. If the slot is inactive, i.e., any of the trackable objects bound by the slot call have been destroyed, then the call to connect is a no-op. If the second version of `connect` is invoked, the slot is associated with the given group. The `at` parameter specifies where the slot should be connected: `at_front` indicates that the slot will be connected at the front of the list or group of slots and `at_back` indicates that the slot will be connected at the back of the list or group of slots.

A ``signals::connection`` object that references the newly-created connection between the signal and the slot; if the slot is inactive, returns a disconnected connection.

This routine meets the strong exception guarantee, where any exception thrown will cause the slot to not be connected to the signal.

Constant time when connecting a slot without a group name or logarithmic in the number of groups when connecting to a particular group.

It is unspecified whether connecting a slot while the signal is calling will result in the slot being called immediately.

void `const group_type&`
void `const Slot&`

If the parameter is (convertible to) a group name, any slots in the given group are disconnected. Otherwise, any slots equal to the given slot are disconnected.

Will not throw unless a user destructor or equality operator `==` throws. If either throws, not all slots may be disconnected.

If a group is given, O(lg g) + k where g is the number of groups in the signal and k is the number of slots in the group. Otherwise, linear in the number of slots connected to the signal.

void

Disconnects all slots connected to the signal.

`this->`empty`()`.

If disconnecting a slot causes an exception to be thrown, not all slots may be disconnected.

Linear in the number of slots known to the signal.

May be called at any time within the lifetime of the signal, including during calls to the signal's slots.

bool

`true` if no slots are connected to the signal, and `false` otherwise.

Will not throw.

Linear in the number of slots known to the signal.

Slots can disconnect at any point in time, including while those same slots are being invoked. It is therefore possible that the implementation must search through a list of disconnected slots to determine if any slots are still connected.

std::size_t

The number of slots connected to the signal

Will not throw.

Linear in the number of slots known to the signal.

Slots can disconnect at any point in time, including while those same slots are being invoked. It is therefore possible that the implementation must search through a list of disconnected slots to determine how many slots are still connected.

result_type `arg1_type` `arg2_type` `...` `argN_type`
result_type `arg1_type` `arg2_type` `...` `argN_type`

Invokes the combiner with a `slot_call_iterator` range [first, last) corresponding to the sequence of calls to the slots connected to signal `*this`. Dereferencing an iterator in this range causes a slot call with the given set of parameters `(a1, a2, ..., aN)`, the result of which is returned from the iterator dereference operation.

The result returned by the combiner.

If an exception is thrown by a slot call, or if the combiner does not dereference any slot past some given slot, all slots after that slot in the internal list of connected slots will not be invoked.

Only the slots associated with iterators that are actually dereferenced will be invoked. Multiple dereferences of the same iterator will not result in multiple slot invocations, because the return value of the slot will be cached.

The `const` version of the function call operator will invoke the combiner as `const`, whereas the non-`const` version will invoke the combiner as non-`const`.

Calling the function call operator may invoke undefined behavior if no slots are connected to the signal, depending on the combiner used. The default combiner is well-defined for zero slots when the return type is void but is undefined when the return type is any other type (because there is no way to synthesize a return value).

combiner_type&
const combiner_type&

A reference to the stored combiner.

Will not throw.

Function type R (T1, T2, ..., TN)
last_value
<R>
int
std::less
<Group>
functionN
<Signature>
signalN
<R, T1, T2, ..., TN, Combiner, Group, GroupCompare, SlotFunction>
Safe multicast callback.

Class template `signal` is a thin wrapper around the numbered class templates `signal0`, `signal1`, etc. It accepts a function type with N arguments instead of N separate arguments, and derives from the appropriate `signalN` instantiation.

All functionality of this class template is in its base class `signalN`.

const combiner_type&
combiner_type()
const group_compare_type&
group_compare_type()

Initializes the base class with the given combiner and comparison objects.