MPI_Bcast
Broadcasts a message from the process with rank "root" to all other processes of the group.
Synopsis
int MPI_Bcast( void *buffer, int count, MPI_Datatype datatype, int root, MPI_Comm comm )
Input/output Parameters
- buffer
- starting address of buffer (choice)
- count
- number of entries in buffer (integer)
- datatype
- data type of buffer (handle)
- root
- rank of broadcast root (integer)
- comm
- communicator (handle)
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 deprecatd. 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_COMM
- Invalid communicator. A common error is to use a null
communicator in a call (not even allowed in MPI_Comm_rank).
- MPI_ERR_COUNT
- Invalid count argument. Count arguments must be
non-negative; a count of zero is often valid.
- MPI_ERR_TYPE
- Invalid datatype argument. May be an uncommitted
MPI_Datatype (see MPI_Type_commit).
- MPI_ERR_BUFFER
- Invalid buffer pointer. Usually a null buffer where
one is not valid.
- 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.
Location:bcast.c