MPICommjoin(3OpenMPI) MPICommjoin(3OpenMPI)

NAME
       MMPPIICCoommmmjjooiinn - Establishes communication between MPI jobs


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       int MPICommjoin(int fd, MPIComm *intercomm)


FFoorrttrraann SSyynnttaaxx
       INCLUDE 'mpif.h'
       MPICOMMJOIN(FD, INTERCOMM, IERROR)
            INTEGER   FD, INTERCOMM, IERROR


CC++++ SSyynnttaaxx
       #include 
       MPI::Intercomm MPI::Comm::Join(const int fd)


IINNPPUUTT PPAARRAAMMEETTEERR
       fd        socket file descriptor (socket).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       intercomm Intercommunicator between processes (handle).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPICommjoin  creates  an  intercommunicator from the union of two MPI
       processes that are connected by a socket. fd is a file descriptor  rep-
       resenting  a socket of type SOCKSTREAM (a two-way reliable byte-stream
       connection). Nonblocking I/O and asynchronous  notification  via  SIGIO
       must  not  be enabled for the socket. The socket must be in a connected
       state, and must be quiescent when MPICommjoin is called.

       MPICommjoin must be called by the process at each end of the  socket.
       It does not return until both processes have called MPICommjoin.


NNOOTTEESS
       There  are  no MPI library calls for opening and manipulating a socket.
       The socket fd can be opened using standard socket API calls.  MPI  uses
       the  socket  to  bootstrap  creation  of the intercommunicator, and for
       nothing else. Upon return, the file descriptor will be open and  quies-
       cent.

       In  a  multithreaded  process,  the  application must ensure that other
       threads do not access the socket while one is in the midst  of  calling
       MPICommjoin.

       The  returned  communicator will contain the two processes connected by
       the socket, and may be used to establish MPI communication  with  addi-
       tional  processes,  through  the usual MPI communicator-creation mecha-
       nisms.


EERRRROORRSS
       Almost all MPI routines return an error value; C routines as the  value
       of  the  function  and Fortran routines in the last argument. C++ func-
       tions do not return errors. If the default  error  handler  is  set  to
       MPI::ERRORSTHROWEXCEPTIONS, 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
       MPICommseterrhandler; the predefined error handler MPIERRORSRETURN
       may be used to cause error values to be returned. Note  that  MPI  does
       not guarantee that an MPI program can continue past an error.

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


SEE ALSO
       socket(3SOCKET)
       MPICommcreate
       MPICommgroup




Open MPI 1.2                    September 2006         MPICommjoin(3OpenMPI)