How to create timer events using C 11

Question

How to create timer events using C   11   I need something like     Call me after 1 second from now      Is there any library

User · Answer

If you are on Windows  you can use the CreateThreadpoolTimer function to schedule a callback without needing to worry about thread management and without blocking the current thread   template lt typename T gt  static void   stdcall timer fired PTP CALLBACK INSTANCE  PVOID context  PTP TIMER timer        CloseThreadpoolTimer timer       std  unique ptr lt T gt  callable reinterpret cast lt T  gt  context          callable        template  lt typename T gt  void call after T callable  long long delayInMs        auto state   std  make unique lt T gt  std  move callable        auto timer   CreateThreadpoolTimer timer fired lt T gt   state get    nullptr       if   timer                throw std  runtime error  Timer               ULARGE INTEGER due      due QuadPart   static cast lt ULONGLONG gt  - delayInMs   10000LL         FILETIME ft      ft dwHighDateTime   due HighPart      ft dwLowDateTime   due LowPart       SetThreadpoolTimer timer   amp ft  0   msPeriod    0   msWindowLength         state release       int main         auto callback                    std  cout  lt  lt   in callback n               call after callback  1000       std  cin get

User · Answer

Made a simple implementation of what I believe to be what you want to achieve  You can use the class later with the following arguments    int  milliseconds to wait until to run the code  bool  if true it returns instantly and runs the code after specified time on another thread  variable arguments  exactly what you d feed to std  bind      You can change std  chrono  milliseconds to std  chrono  nanoseconds or microseconds for even higher precision and add a second int and a for loop to specify for how many times to run the code   Here you go  enjoy    include  lt functional gt   include  lt chrono gt   include  lt future gt   include  lt cstdio gt   class later   public      template  lt class callable  class    arguments gt      later int after  bool async  callable amp  amp  f  arguments amp  amp     args                std  function lt typename std  result of lt callable arguments     gt   type   gt  task std  bind std  forward lt callable gt  f   std  forward lt arguments gt  args                 if  async                        std  thread  after  task                      std  this thread  sleep for std  chrono  milliseconds after                    task                   detach                      else                       std  this thread  sleep for std  chrono  milliseconds after                task                         void test1 void        return     void test2 int a        printf   i n   a       return     int main         later later test1 1000  false   amp test1       later later test2 1000  false   amp test2  101        return 0      Outputs after two seconds   101

User · Answer

This is the code I have so far   I am using VC   2012  no variadic templates     header  include  lt thread gt   include  lt mutex gt   include  lt condition variable gt   include  lt vector gt   include  lt chrono gt   include  lt memory gt   include  lt algorithm gt   template lt class T gt  class TimerThread     typedef std  chrono  high resolution clock clock t     struct TimerInfo         clock t  time point m TimePoint      T m User       template  lt class TArg1 gt      TimerInfo clock t  time point tp  TArg1  amp  amp  arg1          m TimePoint tp          m User std  forward lt TArg1 gt  arg1                    template  lt class TArg1  class TArg2 gt      TimerInfo clock t  time point tp  TArg1  amp  amp  arg1  TArg2  amp  amp  arg2          m TimePoint tp          m User std  forward lt TArg1 gt  arg1   std  forward lt TArg2 gt  arg2                       std  unique ptr lt std  thread gt  m Thread    std  vector lt TimerInfo gt        m Timers    std  mutex                   m Mutex    std  condition variable      m Condition    bool                         m Sort    bool                         m Stop     void TimerLoop           for                  std  unique lock lt std  mutex gt   lock m Mutex          while   m Stop  amp  amp  m Timers empty                    m Condition wait lock                  if  m Stop                  return                 if  m Sort                    Sort could be done at insert           but probabily this thread has time to do         std  sort m Timers begin                      m Timers end                         const TimerInfo  amp  ti1  const TimerInfo  amp  ti2                      return ti1 m TimePoint  gt  ti2 m TimePoint                      m Sort   false                 auto now   clock t  now          auto expire   m Timers back   m TimePoint         if  expire  gt  now    can I take a nap                  auto napTime   expire - now          m Condition wait for lock  napTime              check again         auto expire   m Timers back   m TimePoint          auto now   clock t  now             if  expire  lt   now                      TimerCall m Timers back   m User             m Timers pop back                            else                 TimerCall m Timers back   m User           m Timers pop back                         template lt class T  class TArg1 gt    friend void CreateTimer TimerThread lt T gt  amp  timerThread  int ms  TArg1  amp  amp  arg1      template lt class T  class TArg1  class TArg2 gt    friend void CreateTimer TimerThread lt T gt  amp  timerThread  int ms  TArg1  amp  amp  arg1  TArg2  amp  amp  arg2    public    TimerThread     m Stop false   m Sort false          m Thread reset new std  thread std  bind  amp TimerThread  TimerLoop  this             TimerThread           m Stop   true      m Condition notify all        m Thread- gt join            template lt class T  class TArg1 gt  void CreateTimer TimerThread lt T gt  amp  timerThread  int ms  TArg1  amp  amp  arg1            std  unique lock lt std  mutex gt  lock timerThread m Mutex       timerThread m Timers emplace back TimerThread lt T gt   TimerInfo TimerThread lt T gt   clock t  now     std  chrono  milliseconds ms                                         std  forward lt TArg1 gt  arg1         timerThread m Sort   true           wake up   timerThread m Condition notify one       template lt class T  class TArg1  class TArg2 gt  void CreateTimer TimerThread lt T gt  amp  timerThread  int ms  TArg1  amp  amp  arg1  TArg2  amp  amp  arg2            std  unique lock lt std  mutex gt  lock timerThread m Mutex       timerThread m Timers emplace back TimerThread lt T gt   TimerInfo TimerThread lt T gt   clock t  now     std  chrono  milliseconds ms                                         std  forward lt TArg1 gt  arg1                                         std  forward lt TArg2 gt  arg2         timerThread m Sort   true           wake up   timerThread m Condition notify one         sample  include  lt iostream gt   include  lt string gt   void TimerCall int i      std  cout  lt  lt  i  lt  lt  std  endl     int main       std  cout  lt  lt   start   lt  lt  std  endl    TimerThread lt int gt  timers     CreateTimer timers  2000  1     CreateTimer timers  5000  2     CreateTimer timers  100  3      std  this thread  sleep for std  chrono  seconds 5      std  cout  lt  lt   end   lt  lt  std  endl

User · Answer

Use RxCpp   std  cout  lt  lt   Waiting      lt  lt  std  endl  auto values   rxcpp  observable lt  gt   timer lt  gt  std  chrono  seconds 1    values subscribe    int v   std  cout  lt  lt   Called after 1s    lt  lt  std  endl

User · Answer

The asynchronous solution from Edward    create new thread sleep in that thread do the task in that thread   is simple and might just work for you   I would also like to give a more advanced version which has these advantages    no thread startup overhead only a single extra thread per process required to handle all timed tasks   This might be in particular useful in large software projects where you have many task executed repetitively in your process and you care about resource usage  threads  and also startup overhead   Idea  Have one service thread which processes all registered timed tasks  Use boost io service for that   Code similar to  http   www boost org doc libs 1 65 1 doc html boost asio tutorial tuttimer2 src html   include  lt cstdio gt   include  lt boost asio hpp gt   include  lt boost date time posix time posix time hpp gt   int main       boost  asio  io service io     boost  asio  deadline timer t io  boost  posix time  seconds 1      t async wait    const boost  system  error code amp    e         printf  Printed after 1s n           boost  asio  deadline timer t2 io  boost  posix time  seconds 1      t2 async wait    const boost  system  error code amp    e         printf  Printed after 1s n              both prints happen at the same time       but only a single thread is used to handle both timed tasks      - namely the main thread calling io run       io run       return 0

[c++] How to create timer events using C++ 11?

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