A C++ template library for embedded applications
Designed and maintained by
Aster Consulting Ltd

queue_mpmc_mutex

A fixed capacity multi-producer, multi-consumer queue for multi-threaded systems that uses etl::mutex to control
access.

etl::queue_mpmc_mutex<typename T,
                      const size_t SIZE,
                      const size_t MEMORY_MODEL = etl::memory_model::MEMORY_MODEL_LARGE>

Inherits from etl::iqueue_mpmc_mutex<T>
etl::iqueue_mpmc_mutex may be used as a size independent pointer or reference type for any etl::queue_mpmc_mutex
instance of the same implementation.

The memory model determines the type used internally for indexes and size, to allow for the most efficient
implementation for the application.

Maximum queue sizes:
MEMORY_MODEL_SMALL   255
MEMORY_MODEL_MEDIUM  65535
MEMORY_MODEL_LARGE   2147483647
MEMORY_MODEL_HUGE    9223372036854775807

See memory_model.h

Member types

value_type      T
size_type       <based on memory model>
pointer         value_type*
const_pointer   const value_type*
reference       value_type&
const_reference const value_type&

Constructor

queue_mpmc_mutex();

Capacity

bool empty() const
Returns true if the size of the queue is zero, otherwise false.

bool full() const
Returns true if the size of the queue is SIZE, otherwise false.

size_type size() const
Returns the size of the queue.

size_t available() const
size_t available_from_isr() const
Returns the remaining available capacity in the queue.

ETL_CONSTEXPR size_t max_size() const
Returns the maximum possible size of the queue.

ETL_CONSTEXPR size_t capacity() const
Returns the maximum possible size of the queue.

Modifiers

bool push(parameter_t value);
Pushes a value to the back of the queue.
Returns true if successful, otherwise false.

bool pop();
Pop a value from the front of the list.
Returns true if successful, otherwise false.

bool pop(T& value);
Pop a value from the front of the list and place it in value.
Returns true if successful, otherwise false.

void clear();
Clears the queue to a size of zero.

Notes

Remember that thread context switcches may occur between calls to the access protected functions. For example, a call
to empty() may return true, but a subsequent call to pop() may succeed if a context switch occurred between the two
and pushed a new value.

Example


etl::queue_mpmc_mutex<char, 10> queue;

int main()
{
  while (true)
  {
    char c;

    if (queue.pop(c))
    {
      Print(c);
    }
  }
}

void FunctionInThread1(char c)
{
  while (!queue.push(c))
  {
  }
}

void FunctionInThread2(char c)
{
  while (!queue.push(c))
  {
  }
}
queue_mpmc_isr.h