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MPI_Type_commit

NAME

MPI_Type_commit - Commits a data type.

SYNTAX

C Syntax

 #include <mpi.h>
 int MPI_Type_commit(MPI_Datatype *datatype)
 
 

 

Fortran Syntax

 INCLUDE 'mpif.h'
 MPI_TYPE_COMMIT(DATATYPE, IERROR)
         INTEGER DATATYPE, IERROR 
 
 

 

C++ Syntax

 #include <mpi.h>
 void Datatype::Commit()
 
 

 

INPUT PARAMETER

datatype

Data type (handle).

OUTPUT PARAMETER

IERROR

Fortran only: Error status (integer).

DESCRIPTION

The commit operation commits the data type. A data type is the formal description of a communication buffer, not the content of that buffer. After a data type has been committed, it can be repeatedly reused to communicate the changing content of a buffer or, indeed, the content of different buffers, with different starting addresses.

Example: The following Fortran code fragment gives examples of using MPI_Type_commit.

     INTEGER type1, type2 
     CALL MPI_TYPE_CONTIGUOUS(5, MPI_REAL, type1, ierr) 
                   ! new type object created 
     CALL MPI_TYPE_COMMIT(type1, ierr) 
                   ! now type1 can be used for communication 
 

If the data type specified in datatype is already committed, it is equivalent to a no-op.

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++ functions 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.