Hi,

since you have a separate thread for the accept, you could just set a
flag at the main thread, open a connection from the main thread to match
the accept. The accept thread sees the flag, immediately closes the
connection and leaves the while loop.

  - Joachim

Am 28.01.22 um 05:54 schrieb Rupsa Chakraborty via discuss:
>
> Hello,
>
> I am asking this question in this forum as I had already asked this
> question in stack overflow and did not receive any answer/comment:
> https://stackoverflow.com/questions/70745740/how-to-gracefully-exit-an-mpi-server-process-when-it-is-waiting-on-mpi-comm-acce
> <https://stackoverflow.com/questions/70745740/how-to-gracefully-exit-an-mpi-server-process-when-it-is-waiting-on-mpi-comm-acce>
>
> My concern is as follows:
> I have an MPI server program that calls MPI_Comm_accept, in an infinite
> loop, on a separate thread. The main thread spawns this thread and in
> parallel does some other work. At some point of time the main thread
> decides to exit. It closes the port using MPI_Close_port(portName),
> however the MPI_Comm_accept() is still waiting for connection requests.
>
>
> My question is:
> - How does the main thread exit gracefully? Is there an equivalent of
> socket close in MPI? I am using mpich which I can use from main thread?
>
> - Is there anyway I can set timeout to the MPI_Comm_accept call?
>
> Here is a dummy code that looks similar to my server code:
>
> |// MPI Server Program void accept(std::string portName) { while (true)
> { MPI_Comm intercomm; MPI_Comm_accept(portName.c_str(), MPI_INFO_NULL,
> 0, MPI_COMM_SELF, &intercomm); // handle connection
> MPI_Comm_disconnect(&intercomm); } } int main() { char ch;
> MPI_Init(NULL, NULL); char portName[MPI_MAX_PORT_NAME];
> MPI_Open_port(MPI_INFO_NULL, portName);
> publishName("nameServerFile.txt", "ocean", std::string(portName));
> std::thread th(&accept, std::string(portName)); // do something
> MPI_Close_port(portName); std::cout <<"\nClosed port" << std::endl;
> th.join(); // main thread waits infinitely at this join // as child
> thread is still waiting on MPI_Comm_accept MPI_Finalize(); }|
>
>
>
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--
Dr. rer. nat. Joachim Protze

IT Center
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