CODEWITHSUNDEEP
c++windows
James
James

Reputation: 11

Windows C++ Code (similar to CRON) that executes a command every xx hours

In the situation I am faced with, I am in need of some code in C++ that will execute a command every 2 hours, although I do not program in C++ (rather C#), but in this instance I am unable to use C#.

Could someone provide an example code that demonstrates this please

Upvotes: 1

Views: 927

Answers (3)

user208608
user208608

Reputation:

Use the C++ service wizard to create the service, and plug this into the service (with more error trapping, of course). This should work with most modern versions of Windows.

#include "stdafx.h"
#include <windows.h>
#include <iostream>
using namespace std;


/**
A callback function.  It is similar to a delegate in .Net.
*/
VOID CALLBACK theTimerCallback(PVOID aParam, BOOLEAN TimerOrWaitFired)
{
  // This is executed when the timer fires.
  cout << "The timer says: Hello, world." << endl;

  // The parameter (see below) is a handle to single the 
  // main thread to shut down.
  HANDLE theShutdownEvent = (HANDLE)aParam;

  // Tell the main thread to shutdown.
  SetEvent (theShutdownEvent);
}



int _tmain(int argc, _TCHAR* argv[])
{

  // Assuming you have a program running some main thread, this
  // will run a timer in the background and handle the timer callbacks.
  // So if this is a service, this timer would execute while the main
  // service thread can handle startup and shutdown of the service.

  // If it is just a single thread of an application that you manually
  // execute, then using a sleep in a loop would work fine.


  // Creating an event to make this main thread wait.
  HANDLE anEventHandle = CreateEvent (NULL, TRUE, FALSE, L"Shutdown event");


  // The queue object that handles the timers
  HANDLE theTimerQueueHandle = CreateTimerQueue ();


  HANDLE theTimerHandle = NULL; 

  if (CreateTimerQueueTimer (
    &theTimerHandle, // The handle to the timer is written to this variable.
    theTimerQueueHandle, // The handle to the timer queue that tracks this timer.
    theTimerCallback, // The callback function (see above).
    anEventHandle, // A parameter sent to the callback function.  This can be anything.
    10000, // Time to fire, in milliseconds (10 secs).
    0, // Execution period - 0 means it only fires once.
    WT_EXECUTEDEFAULT // Look at the API docs and pick your own flags.
    ) )
  {
    cout << "Main thread waiting for timer." << endl;
    // This makes the main thread wait until the timer fires.  Normally, something like
    // a service would have its own mechanism of waiting on the main thread.
    WaitForSingleObject (anEventHandle, INFINITE);


    // This shuts down all the timers, deletes their handles, waits for
    // handler functions to finish, and deletes the timer handles as well
    // as the queue handle.
    DeleteTimerQueueEx (theTimerQueueHandle, INVALID_HANDLE_VALUE);

  }

  CloseHandle (anEventHandle);

  cout << "Main thread exiting" << endl;
    return 0;
}

Upvotes: 0

TarunG
TarunG

Reputation: 610

c++ standard libraries do not provide any option similar to c# timers, you can use sleep, but that would suspend the thread,

A not-so-very-accurate workaround will be to get the time from clock on initialization,

and placing a check within some regularly executing block to see if time>init+step and then jump of to your timer statements and reset init = cur_time..

or you can use windows timer :

http://www.cplusplus.com/forum/beginner/11271/ http://www.cplusplus.com/forum/windows/5531/

Upvotes: 0

Ben Usman
Ben Usman

Reputation: 8387

Probably ,something simple like this?:

VOID WINAPI Sleep(
__in  DWORD dwMilliseconds
);

.

while (true)
{
   dosmt();
   sleep(2*60*60*1000);
}

Or start it in a single thread in case it should be executed parallel to remaining programm? It this case boost::thread can help.

Upvotes: 1

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