signal

20.42.0

A class that implements simple signal/slot framework.

Uses etl::delegate as the default slot type, though other types may be used.

template <typename TFunction, size_t Size, typename TSlot = etl::delegate<TFunction>>

class signal

TFunction The callback function signature.

Size The maximum numbr of slots for the signal.

TSlot The callback slot type. Default = etl::delegate<TFunction>

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Types

slot_type Defined as the slot type.

size_type The size type used internally.

span_type The span type used in the connect API.

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Constructors

template <typename... TSlots>

ETL_CONSTEXPR14 explicit signal(TSlots&&... slots) ETL_NOEXCEPT

Construct the signal from a variadic list of slots.

Can be used as a constexpr constructor.

Static asserts if any of the

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Connect

bool connect(const slot_type& slot)

Connects the slot, if not already connected and returns true.

If the signal is full, ETL_ASSERTs etl::signal_full and returns false.

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bool connect(std::initializer_list<const slot_type> slots)

Connects all of the slots and returns true.

If the number of slots exceeds the signal's max size, asserts an etl::signal_full and returns false.

Enabled if ETL_HAS_INITIALIZER_LIST and ETL_USING_CPP17 are defined as 1.

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bool connect(const span_type slots)

Connects all of the slots and returns true.

If the number of slots exceeds the signal's max size, asserts an etl::signal_full and returns false.

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Disconnect

void disconnect(const slot_type& slot) ETL_NOEXCEPT

Disconnects slot from the signal.

If the signal does not contain the slot. there is no error.

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void disconnect(std::initializer_list<const slot_type> slots) ETL_NOEXCEPT

Disconnects all of the slots from the signal.

If the signal does not contain a particular slot, there is no error.

Enabled if ETL_HAS_INITIALIZER_LIST and ETL_USING_CPP17 are defined as 1.

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void disconnect(const span_type slots) ETL_NOEXCEPT

Disconnects all of the slots from the signal.

If the signal does not contain a particular slot, there is no error.

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void disconnect_all() ETL_NOEXCEPT

Disconnects all slots from the signal.

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Status

ETL_CONSTEXPR14 bool connected(const slot_type& slot) const ETL_NOEXCEPT

Checks if a slot is connected to the signal.

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ETL_CONSTEXPR14 bool empty() const ETL_NOEXCEPT

Return true if the signal has no slots connected.

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ETL_CONSTEXPR14 bool full() const ETL_NOEXCEPT

Return true if the signal has the maximum number of slots connected.

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ETL_CONSTEXPR14 size_type max_size() const ETL_NOEXCEPT

Returns the total number of slots that can be connected.

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ETL_CONSTEXPR14 size_type size() const ETL_NOEXCEPT

Returns the total slots currently connected.

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ETL_CONSTEXPR14 size_type available() const ETL_NOEXCEPT

Returns the total empty slots available.

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Call

template <typename... TArgs>

void operator()(TArgs&&... args) const ETL_NOEXCEPT

Function operator that calls each slot with the supplied parameters.

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Errors

etl::signal_full Indicates that an attempt to add a slot to a full signal occurred.

Inherits from etl::signal_exception

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Examples

constexpr size_t MaxSlots = 3;

using callback_type = void(int a, int b);

using signal_type = etl::signal<callback_type, MaxSlots>;

using slot_type = signal_type::slot_type;

using span_type = signal_type::span_type;

using not_slot_type = etl::delegate<void(int)>;

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Defining the slot functions

void Function1(int a, int b)

{

std::cout << "Function1: " << a << "," << b << "\n";

}

void Function2(int a, int b)

{

std::cout << "Function2: " << a << "," << b << "\n";

}

void Function3(int a, int b)

{

std::cout << "Function3: " << a << "," << b << "\n";

}

void Function4(int a, int b)

{

std::cout << "Function4: " << a << "," << b << "\n";

}

void Function5(int a)

{

std::cout << "Function5: " << a << "\n";

}

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Creating the slots

constexpr slot_type MakeSlot1() noexcept

{

return slot_type::create<Function1>();

}

constexpr slot_type MakeSlot2() noexcept

{

return slot_type::create<Function2>();

}

constexpr slot_type MakeSlot3() noexcept

{

return slot_type::create<Function3>();

}

constexpr slot_type MakeSlot4() noexcept

{

return slot_type::create<Function4>();

}

constexpr not_slot_type MakeSlot5() noexcept

{

return not_slot_type::create<Function5>();

}

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Defining the signal as constexpr

// Define the signal and connect as constexpr

constexpr signal_type({ MakeSlot1(), MakeSlot2(), MakeSlot3() });

// Define the signal and connect as constexpr.

// Static assert "Number of slots exceeds capacity"

constexpr signal_type({ MakeSlot1(), MakeSlot2(), MakeSlot3(), MakeSlot4() });

// Define the signal and connect as constexpr.

// Static assert "All slots must be slot_type"

constexpr signal_type({ MakeSlot1(), MakeSlot2(), MakeSlot5() });

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Defining the signal at runtime

// Define the signal.

signal_type signal;

// Connect one at a time.

signal.connect(MakeSlot1());

signal.connect(MakeSlot2());

signal.connect(MakeSlot3());

// Connect using initializer_list.

signal.connect({ MakeSlot1(), MakeSlot2(), MakeSlot3() });

// Connect using span.

const slot_type slot_list[] = { MakeSlot1(), MakeSlot2(), MakeSlot3() };

signal.connect(slot_list);

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Checking the status

// Define the signal.

signal_type signal;

signal.max_size() // Returns 3

signal.size() // Returns 0

signal.available() // Returns 3

signal.empty(); // Returns true

signal.full(); // Returns false

signal.connected(MakeSlot1()) // Returns false

signal.connected(MakeSlot2()) // Returns false

signal.connected(MakeSlot3()) // Returns false

signal.connect(MakeSlot1()); // Returns true

signal.max_size() // Returns 3

signal.size() // Returns 1

signal.available() // Returns 2

signal.empty(); // Returns false

signal.full(); // Returns false

signal.connected(MakeSlot1()) // Returns true

signal.connected(MakeSlot2()) // Returns false

signal.connected(MakeSlot3()) // Returns false

signal.connect(MakeSlot1()); // Already connected. Returns true

signal.max_size() // Returns 3

signal.size() // Returns 1

signal.available() // Returns 2

signal.empty(); // Returns false

signal.full(); // Returns false

signal.connected(MakeSlot1()) // Returns true

signal.connected(MakeSlot2()) // Returns false

signal.connected(MakeSlot3()) // Returns false

signal.connect(MakeSlot2()); // Returns true

signal.max_size() // Returns 3

signal.size() // Returns 2

signal.available() // Returns 1

signal.empty(); // Returns false

signal.full(); // Returns false

signal.connected(MakeSlot1()) // Returns true

signal.connected(MakeSlot2()) // Returns true

signal.connected(MakeSlot3()) // Returns false

signal.connect(MakeSlot3()); // Returns true

signal.max_size() // Returns 3

signal.size() // Returns 3

signal.available() // Returns 0

signal.empty(); // Returns false

signal.full(); // Returns true

signal.connected(MakeSlot1()) // Returns true

signal.connected(MakeSlot2()) // Returns true

signal.connected(MakeSlot3()) // Returns true

signal.connect(MakeSlot4()); // ETL_ASSERT etl::signal_full. Returns false

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Calling the signal

signal_type signal({ MakeSlot1(), MakeSlot2(), MakeSlot3() });

signal(1, 2); // Call all of the slots with the parameters 1 & 2

Output

Function1: 1,2

Function2: 1,2

Function3: 1,2

signal.h