sigc::signal< T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7 >::signal::accumulated< T_accumulator > Class Template Reference
[Signals]
Convenience wrapper for the numbered sigc::signal# templates. More...
Inherits signal7< T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7, T_accumulator >.
Public Member Functions | |
accumulated (const accumulated& src) |
Detailed Description
template <class T_return, class T_arg1 = nil, class T_arg2 = nil, class T_arg3 = nil, class T_arg4 = nil, class T_arg5 = nil, class T_arg6 = nil, class T_arg7 = nil>
template <class T_accumulator>
class sigc::signal< T_return, T_arg1, T_arg2, T_arg3, T_arg4, T_arg5, T_arg6, T_arg7 >::accumulated< T_accumulator >
Convenience wrapper for the numbered sigc::signal# templates. Like sigc::signal but the additional template parameter T_accumulator defines the accumulator type that should be used.
An accumulator is a functor that uses a pair of special iterators to step through a list of slots and calculate a return value from the results of the slot invokations. The iterators' operator*() executes the slot. The return value is buffered, so that in an expression like
a = (* i)* (* i);
result_type
.
- Example 1:
- This accumulator calculates the arithmetic mean value:
struct arithmetic_mean_accumulator { typedef double result_type; template<typename T_iterator> result_type operator()(T_iterator first, T_iterator last) const { result_type value_ = 0; int n_ = 0; for (; first != last; ++first, ++n_) value_ += *first; return value_ / n_; } };
- Example 2:
- This accumulator stops signal emission when a slot returns zero:
struct interruptable_accumulator { typedef bool result_type; template<typename T_iterator> result_type operator()(T_iterator first, T_iterator last) const { for (; first != last; ++first, ++n_) if (!*first) return false; return true; } };
The documentation for this class was generated from the following file:
- sigc++/signal.h