making a non blocking timer in c++

[mohtasham1983]

Hello everybody,
I am trying to make a C++ timer on windows which has following functionality:

Once the function is called, timer should start and last for 10 seconds, but in this period of time, it shouldn’t block other functions working.

I mean if timer should run in background and if it reaches to 10, a special function should be called and timer value should be reset.

If timer doesn’t reach to 10 and gets call for the second time, it should be reset to zero and start again.

Counter=0;
Void function()
{
if (counter == 0)
    time (&start);
::counter++;
 
for ( ; ; )
{
if (elapsed_time = difftime(time( &finish ), start )>10)
    {
        cout << "Time out Has Occurd" << endl;
        time( &start );
    }             
}
}
 
 

But this function is blocking other functions.

Is there any other command that can help me?

[Savage]

Hello everybody,
I am trying to make a C++ timer on windows which has following functionality:

Once the function is called, timer should start and last for 10 seconds, but in this period of time, it shouldn’t block other functions working.

I mean if timer should run in background and if it reaches to 10, a special function should be called and timer value should be reset.

If timer doesn’t reach to 10 and gets call for the second time, it should be reset to zero and start again.

Counter=0;
Void function()
{
if (counter == 0)
    time (&start);
::counter++;
 
for ( ; ; )
{
if (elapsed_time = difftime(time( &finish ), start )>10)
    {
        cout << "Time out Has Occurd" << endl;
        time( &start );
    }             
}
}
 
 

But this function is blocking other functions.

Is there any other command that can help me?

What is that special function?

Is user inputing something when function is called?

If it input u could do something like:

time(&start);
 
do{
           spec_func();
           time(&finish);
           time=finish-start;
           if(time<=10)print_out_time();
           else time=0;
 
}while(user_don't_press_any_key or while function executes);

Savage

[mohtasham1983]

it is a function used to send a packet.

Actually it's a thread which should sends a packet and if time out happens, it should retransmit it. I cannot use global variable either, since it may conflict with other threads.

By the way, there is a method using waitable timer in
http://msdn2.microsoft.com/en-us/library/ms687008.aspx

But I am not sure if it suits my needs, because my program is a pure c++ one.

I even tried to use settimer function, but i couldn't figure out how to use it.

[weaknessforcats]

Research Win32 CreateThread() and put your timer in a function whose address and arguments are passed to CreateThread(). The timer will happily run on its own thread without bothering the main thread.

You will find your thread must be a ThreadProc (more research) and you may have to call your real function from the ThreadProc that you used with CreateThread().

You can communicate with this thread using WaitForSingleObject() and an event (more research on CreateEvernt()).

[mohtasham1983]

I am trying to find a way to solve it without using win32 special APIs.

I tried so:

class Timer {
    clock_t counter;
public:
    Timer(): counter(0) {};
 
    bool elasped(clock_t ms)
    {
        clock_t tick = std::clock();
 
        if(tick - counter >= ms)
        {
             counter = tick;
             return true;
        }
 
        return false;
    }
};
 

and then i placed this inside my thread:

Timer timer;
 
while(true) {
    if(timer.elasped(20000)) {
        log(ServerPacketBuffer,1,1,0);
        udp_server_send(send_buffer, packet_length, client[slavenum].clientAddr);    // Send packet
        cout << "Time out Has Occurd" << endl;
    }
}        
 

This one is non blocking, but i cannot reset it

[Savage]

I am trying to find a way to solve it without using win32 special APIs.

I tried so:

class Timer {
    clock_t counter;
public:
    Timer(): counter(0) {};
 
    bool elasped(clock_t ms)
    {
        clock_t tick = std::clock();
 
        if(tick - counter >= ms)
        {
             counter = tick;
             return true;
        }
 
        return false;
    }
};
 

and then i placed this inside my thread:

Timer timer;
 
while(true) {
    if(timer.elasped(20000)) {
        log(ServerPacketBuffer,1,1,0);
        udp_server_send(send_buffer, packet_length, client[slavenum].clientAddr);    // Send packet
        cout << "Time out Has Occurd" << endl;
    }
}        
 

This one is non blocking, but i cannot reset it

How do u mean u cannot reset it?

Have u tryed initialize start and finish time again?

Savage

[weaknessforcats]

I am trying to find a way to solve it without using win32 special APIs.

By default any C++ program is single-threaded. You simply can't do two things at once. You will need to create a worker thread (daemon) that can run independently of the main thread.

Threads are controlled by the OS. Wins32 is your interface to the OS.