MPI_Comm_accept - Establishes communication with a client.

       #include <mpi.h>
       int MPI_Comm_accept(const char *port_name, MPI_Info info, int root, MPI_Comm comm, MPI_Comm *newcomm)

       #include <mpi.h>
       MPI::Intercomm MPI::Intracomm::Accept(const char* port_name,
            const MPI::Info& info, int root) const

       MPI_Comm_accept establishes communication with a client. It is collective over the calling  communicator.
       It returns an intercommunicator that allows communication with the client, after the client has connected
       with the MPI_Comm_accept function using the MPI_Comm_connect function.

       The port_name must have been established through a call to MPI_Open_port on the root.

       Almost  all  MPI  routines  return  an  error  value; C routines as the value of the function and Fortran
       routines in the last argument. C++ functions do not return errors. If the default error handler is set to
       MPI::ERRORS_THROW_EXCEPTIONS, then on error the  C++  exception  mechanism  will  be  used  to  throw  an
       MPI::Exception object.

       Before  the  error  value  is  returned,  the current MPI error handler is called. By default, this error
       handler aborts the MPI job, except for I/O function  errors.  The  error  handler  may  be  changed  with
       MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values
       to be returned.

       See the MPI man page for a full list of MPI error codes.

       USE mpi_f08
       MPI_Comm_accept(port_name, info, root, comm, newcomm, ierror)
            CHARACTER(LEN=*), INTENT(IN) :: port_name
            TYPE(MPI_Info), INTENT(IN) :: info
            INTEGER, INTENT(IN) :: root
            TYPE(MPI_Comm), INTENT(IN) :: comm
            TYPE(MPI_Comm), INTENT(OUT) :: newcomm
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_COMM_ACCEPT(PORT_NAME,INFO,ROOT,COMM,NEWCOMM,IERROR)
            CHARACTER*(*)  PORT_NAME
            INTEGER        INFO,ROOT,COMM,NEWCOMM,IERROR

       port_name Port name (string, used only on root).

       info      Options  given  by  root  for  the  accept  (handle,  used  only on root). No options currently
                 supported.

       root      Rank in comm of root node (integer).

       comm      Intracommunicator over which call is collective (handle).

MPI_Comm_accept  - Establishes communication with a client.

       newcomm   Intercommunicator with client as remote group (handle)

       IERROR    Fortran only: Error status (integer).

       MPI_Comm_connect MPI_Open_port

4.1.2                                             Nov 24, 2021                         MPI_Comm_accept(3OpenMPI)