Class template counter

Boost C++ Libraries

Class template counter

boost::log::attributes::counter — A class of an attribute that counts an integral value.

Synopsis

// In header: <boost/log/attributes/counter.hpp>

template<typename T> 
class counter : public attribute {
public:
  // types
  typedef T held_type;  // A held counter type. 

  // construct/copy/destruct
  explicit counter(held_type const & = held_type(), long = 1);

  // public member functions
  shared_ptr< attribute_value > get_value();
};

Description

This type of attribute acts as a counter, that is, it returns a monotonously changing value each time requested. The attribute value type can be specified as a template parameter. However, the type must support basic arithmetic operations, such as addition and substraction.

`counter` public construct/copy/destruct

```
explicit counter(held_type const & initial = held_type(), long step = 1);
```
Constructor

Parameters:

initial
Initial value of the counter

step
Changing step of the counter. Each value acquired from the attribute will be greater than the previous one to this amount.

`counter` public member functions

```
shared_ptr< attribute_value > get_value();
```
Returns:
The actual attribute value. It shall not return NULL (exceptions shall be used to indicate errors).