debian man page for mpi_comm_join

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)