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mpi_comm_join(3openmpi) [osx man page]

MPI_Comm_join(3OpenMPI) 												   MPI_Comm_join(3OpenMPI)

NAME
MPI_Comm_join - Establishes communication between MPI jobs SYNTAX
C Syntax #include <mpi.h> int MPI_Comm_join(int fd, MPI_Comm *intercomm) Fortran Syntax INCLUDE 'mpif.h' MPI_COMM_JOIN(FD, INTERCOMM, IERROR) INTEGER FD, INTERCOMM, IERROR C++ Syntax #include <mpi.h> MPI::Intercomm MPI::Comm::Join(const int fd) INPUT PARAMETER
fd socket file descriptor (socket). OUTPUT PARAMETERS
intercomm Intercommunicator between processes (handle). IERROR Fortran only: Error status (integer). DESCRIPTION
MPI_Comm_join 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 SOCK_STREAM (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 MPI_Comm_join is called. MPI_Comm_join must be called by the process at each end of the socket. It does not return until both processes have called MPI_Comm_join. NOTES
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 quiescent. In a multithreaded process, the application must ensure that other threads do not access the socket while one is in the midst of calling MPI_Comm_join. 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 mechanisms. ERRORS
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::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. 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) MPI_Comm_create MPI_Comm_group Open MPI 1.2 September 2006 MPI_Comm_join(3OpenMPI)

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MPI_Comm_join(3)							MPI							  MPI_Comm_join(3)

NAME
MPI_Comm_join - Create a communicator by joining two processes connected by a socket. SYNOPSIS
int MPI_Comm_join(int fd, MPI_Comm *intercomm) INPUT PARAMETER
fd - socket file descriptor OUTPUT PARAMETER
intercomm - new intercommunicator (handle) NOTES
The socket must be quiescent before MPI_COMM_JOIN is called and after MPI_COMM_JOIN returns. More specifically, on entry to MPI_COMM_JOIN , a read on the socket will not read any data that was written to the socket before the remote process called MPI_COMM_JOIN . THREAD AND INTERRUPT SAFETY
This routine is thread-safe. This means that this routine may be safely used by multiple threads without the need for any user-provided thread locks. However, the routine is not interrupt safe. Typically, this is due to the use of memory allocation routines such as malloc or other non-MPICH runtime routines that are themselves not interrupt-safe. NOTES FOR FORTRAN
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the end of the argument list. ierr is an integer and has the same meaning as the return value of the routine in C. In Fortran, MPI routines are subroutines, and are invoked with the call statement. All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran. ERRORS
All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error value; C routines as the value of the function and Fortran routines in the last argument. Before the value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job. The error handler may be changed with MPI_Comm_set_errhandler (for communicators), MPI_File_set_errhandler (for files), and MPI_Win_set_errhandler (for RMA windows). The MPI-1 routine MPI_Errhandler_set may be used but its use is deprecated. The predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue past an error; however, MPI implementations will attempt to continue whenever possible. MPI_SUCCESS - No error; MPI routine completed successfully. MPI_ERR_ARG - Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., MPI_ERR_RANK ). LOCATION
comm_join.c 7/27/2010 MPI_Comm_join(3)
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