[LCP]Help in Parallel tasks

[Andrew Weaver]

Well, it seems that what you are looking for is for the child to know that
the parent has issued its ping. So, have the parent set the semaphore just
ahead of its "system" call and have the child test the semaphore (not block
on it). Make sure that the parent pings for long enough to enable the child
to do two snmpgets.

On Thursday, November 21, 2002 10:16 AM, Mohd Saifullah
[SMTP:saif at lantana.tenet.res.in] wrote:
> 
> Yes, i have used semaphores. But i can use them before or after the "ping"

> only. What i need is: during "ping". 
> 
> Regards,
> Saif
> 
> On Thu, 21 Nov 2002, Andrew Weaver wrote:
> 
> > Well, these are not "threads". Have you explored semaphores? 
> > 
> > On Thursday, November 21, 2002 6:14 AM, Mohd Saifullah
> > [SMTP:saif at lantana.tenet.res.in] wrote:
> > > 
> > > Hello,
> > > 
> > > I am appending the code that i am trying out (this time with
processes).
> > > 
> > > main()
> > > {
> > >   int upid;
> > >   upid =  fork();
> > >   if(upid == 0)
> > >     {
> > >       system("snmpget localhost public .1.3.6.1.2.1.2.2.1.10.2 >
file1");
> > 
> > >       usleep(1000000);
> > >       system("snmpget localhost public .1.3.6.1.2.1.2.2.1.10.2 >>
file1");
> > >       exit(0);
> > >     }
> > >   else
> > >     {
> > >     system("ping -i 0.01 -c 100 -s 954 -q fileserver > pingout");
> > >     }
> > > }
> > > 
> > > My exact requirement is: the first snmpget of child process has to be
> > > executed little after parent process starts "ping". And also the
second
> > > snmpget of child process has to run before parent process stops
pingning.
> > > 
> > > Any idea, please?
> > > 
> > > Regards,
> > > Saif 
> > > 
> > > 
> > >  On Wed, 20 Nov 2002, David wrote:
> > > 
> > > > Mohd Saifullah wrote:
> > > > > Greetings to All!
> > > > > 
> > > > > I have written two threads (Linux pthreads). One thread does
"ping"ing
> > for
> > > > > two to three secs. The other thread has to note down the interface
> > traffic
> > > > > count at the beginning of the pinging and also at the end of it,
so
> > this
> > > > > thread has 2 secs sleep in between the two readings. But the
problem
> > is:  
> > > > > first thread is executed completely and then control comes to
second 
> > > > > thread. But i want control to switch from first thread to second
> > thread as
> > > > > soon as first one starts pinging.
> > > > > 
> > > > > Thanks in advance,
> > > > > Saif
> > > > > 
> > > > 
> > > > Have you thought using a condition variable?  You could use it make
the 
> > > > first thread signal the second and wait until the second thread
> > completes.
> > > > The second thread could then signal the first when it is finished.
> > > > 
> > > > 
> > > 
> > > _______________________________________________
> > > This is the Linux C Programming List
> > > :  http://lists.linux.org.au/listinfo/linuxcprogramming List
> > _______________________________________________
> > This is the Linux C Programming List
> > :  http://lists.linux.org.au/listinfo/linuxcprogramming List
> > 
> 
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