MPI_Comm_join(3) LAM/MPI MPI_Comm_join(3)
MPI_Comm_join - Connect two MPI processed joined by a socket
MPI_Comm_join(int fd, MPI_Comm *newcomm)
fd - socket file descriptor
- intercommunicator with client as remote group
This function only works between two LAM/MPI processes that are connected by a socket.
They either must have the same endian orientation, or not have used the homogeneous flag
to mpirun (1) (-O). Both processes must be in a single LAM universe -- they must share
LAM daemons that are already connected to each other. That is, they were either initially
lamboot(1)ed together, or a lamgrow(1) command was given to grow an initial LAM universe
such that the resulting set includes the two hosts in question.
Once this call completes successfully, fd may not be used by the caller for any reason.
LAM will eventually close the socket (possibly as late as during MPI_Finalize (3)).
NOTES FOR FORTRAN
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argu-
ment 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.
USAGE WITH IMPI EXTENSIONS
The IMPI standard only supports MPI-1 functions. Hence, this function is currently not
designed to operate within an IMPI job.
If an error occurs in an MPI function, the current MPI error handler is called to handle
it. By default, this error handler aborts the MPI job. The error handler may be changed
with MPI_Errhandler_set ; the predefined error handler MPI_ERRORS_RETURN may be used to
cause error values to be returned (in C and Fortran; this error handler is less useful in
with the C++ MPI bindings. The predefined error handler MPI::ERRORS_THROW_EXCEPTIONS
should be used in C++ if the error value needs to be recovered). Note that MPI does not
guarantee that an MPI program can continue past an error.
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. The C++ bindings for
MPI do not return error values; instead, error values are communicated by throwing excep-
tions of type MPI::Exception (but not by default). Exceptions are only thrown if the
error value is not MPI::SUCCESS
Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI functions will return
upon an error, there will be no way to recover what the actual error value was.
- No error; MPI routine completed successfully.
- Invalid argument. Some argument is invalid and is not identified by a specific
error class. This is typically a NULL pointer or other such error.
- An internal error has been detected. This is fatal. Please send a bug report to
the LAM mailing list (see http://www.lam-mpi.org/contact.php ).
- Other error; use MPI_Error_string to get more information about this error code.
lamboot(1), lamgrow(1), mpirun(1), MPI_Finalize(3)
For more information, please see the official MPI Forum web site, which contains the text
of both the MPI-1 and MPI-2 standards. These documents contain detailed information about
each MPI function (most of which is not duplicated in these man pages).
LAM/MPI 6.5.8 11/10/2002 MPI_Comm_join(3)