edm::CallNTimesNoWait Class Reference

#include "CallNTimesNoWait.h"

Public Member Functions
	CallNTimesNoWait (unsigned short iNTimes)
template<typename T >
void	operator() (T iCall)

Private Attributes
std::atomic< bool >	m_done
std::atomic< int >	m_ntimes

Detailed Description

Description: Thread safe way to do something N times

Usage: This class allows one to safely do a 'non-side-effect' operation N times in a job. An example use would be

void myFunc( int iValue) {
  static CallNTimesNoWait message{2};
  message([&]() { edm::LogInfo("IWantToKnow")<<"called with "<<iValue; } );

The important thing to remember, is there is no guarantee that the operation being run finishes before a thread which doesn't get to run the operation reaches the code following the call. Therefore it is useful to suppress messages but should not be used to do something like filling a container with values since the filling is not guaranteed to complete before another thread skips the call.

Definition at line 38 of file CallNTimesNoWait.h.

Constructor & Destructor Documentation

CallNTimesNoWait()

edm::CallNTimesNoWait::CallNTimesNoWait ( unsigned short  iNTimes )

inline

Definition at line 40 of file CallNTimesNoWait.h.

: m_ntimes(static_cast<int>(iNTimes) - 1), m_done(false) {}

Member Function Documentation

operator()()

template<typename T >

void edm::CallNTimesNoWait::operator() ( T  iCall )

inline

Definition at line 43 of file CallNTimesNoWait.h.

References m_done, and m_ntimes.

                             {
      if (not m_done.load(std::memory_order_acquire)) {
        if (m_ntimes.fetch_sub(1, std::memory_order_acq_rel) < 0) {
          m_done.store(true, std::memory_order_release);
          return;
        };
        iCall();
      }
    }

Member Data Documentation

m_done

std::atomic<bool> edm::CallNTimesNoWait::m_done

private

Definition at line 55 of file CallNTimesNoWait.h.

Referenced by operator()().

m_ntimes

std::atomic<int> edm::CallNTimesNoWait::m_ntimes

private

Definition at line 54 of file CallNTimesNoWait.h.

Referenced by operator()().