Package: src/packages/rtl-waitablebool.fdoc

Waitable bool

key	file
pthread_waitable_bool.hpp	share/lib/rtl/pthread_waitable_bool.hpp
pthread_waitable_bool.cpp	share/src/pthread/pthread_waitable_bool.cpp

Shared Boolean

Used by demux_quitter

//[pthread_waitable_bool.hpp]
#ifndef __FLX_PTHREAD_WAIT_BOOL_H__
#define __FLX_PTHREAD_WAIT_BOOL_H__
#include "flx_pthread_config.hpp"
#include <thread>
#include <mutex>
#include <condition_variable>

namespace flx { namespace pthread {

// a waitable boolean.
class PTHREAD_EXTERN waitable_bool {
  ::std::mutex cv_lock;       // to work with the condition var
  ::std::condition_variable_any finished_cond;
  bool finished;   // might seem redundant, but that's how CVs work.
public:
  waitable_bool();

  void wait_until_true();
  void signal_true();
};

}} // namespace pthread, flx
#endif // __FLX_PTHREAD_WAIT_BOOL_H__

//[pthread_waitable_bool.cpp]
#include "pthread_waitable_bool.hpp"

namespace flx { namespace pthread {

waitable_bool::waitable_bool()
  : finished(false)
{
  // nothing
}

// can be called from any thread
void
waitable_bool::wait_until_true()
{
  ::std::unique_lock< ::std::mutex> locker(cv_lock);

  // wait for the wakeup to say it's finished
  while(!finished)
  {
    finished_cond.wait(cv_lock);
  }
}

void
waitable_bool::signal_true()
{
  { // the mutex is required for the memory barrier..
    ::std::unique_lock< ::std::mutex> locker(cv_lock);
    finished = true;
  }
  finished_cond.notify_all();
  // do absolutely NOTHING here as a typical use of this class is to
  // wait for a thread exit and then destruct its resources, which could
  // very well include this object. boom.
}

} }