NAME¶
MPI_Comm_connect - Make a connection to another MPI process
SYNOPSIS¶
#include <mpi.h>
int
MPI_Comm_connect(char *port_name, MPI_Info info, int root, MPI_Comm comm,
MPI_Comm *newcomm)
- port_name
- - port name (only used at root)
- info
- - extra information handle (only used at root)
- root
- - rank in comm of root node
- comm
- - intracommunicator over which the call is collective
OUTPUT PARAMETER¶
- newcomm
- - intercommunicator with server as remote group
DESCRIPTION¶
The
MPI_Comm_accept and
MPI_Comm_connect calls simulate the
well-understood
accept() /
connect() semantics of standard
socket programming -- a client "connects" to a server.
LAM/MPI allows for previously-unrelated MPI programs to join into a MPI program
with these calls. Both MPI programs must be running by the same user in the
same LAM universe (i.e., in the scope of a single lamboot).
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.
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.
ERRORS¶
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 exceptions 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.
- MPI_SUCCESS
- - No error; MPI routine completed successfully.
- MPI_ERR_COMM
- - Invalid communicator. A common error is to use a null communicator in a
call (not even allowed in MPI_Comm_rank ).
- MPI_ERR_ROOT
- - Invalid root. The root must be specified as a rank in the communicator.
Ranks must be between zero and the size of the communicator minus
one.
- MPI_ERR_ARG
- - 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.
- MPI_ERR_INTERN
- - 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 ).
- MPI_ERR_OTHER
- - Other error; use MPI_Error_string to get more information about
this error code.
- MPI_ERR_FLAGS
- - Mismatch of run-time flags. For example, an MPI process that is running
in lamd mode cannot spawn or be connected to a process that is running in
c2c mode.
SEE ALSO¶
MPI_Close_port(3),
MPI_Comm_accept(3),
MPI_Open_port(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).
http://www.mpi-forum.org/
LOCATION¶
connect.c