MPI_Type_struct(3)                 Open MPI                 MPI_Type_struct(3)



NAME
       MPI_Type_struct - Creates a struct data type -- use of this routine is
       deprecated.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Type_struct(int count, int *array_of_blocklengths,
            MPI_Aint *array_of_displacements, MPI_Datatype *array_of_types,
            MPI_Datatype *newtype)


Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_TYPE_STRUCT(COUNT, ARRAY_OF_BLOCKLENGTHS,
                 ARRAY_OF_DISPLACEMENTS, ARRAY_OF_TYPES,
                 NEWTYPE, IERROR)
            INTEGER   COUNT, ARRAY_OF_BLOCKLENGTHS(*)
            INTEGER   ARRAY_OF_DISPLACEMENTS(*)
            INTEGER   ARRAY_OF_TYPES(*), NEWTYPE, IERROR



INPUT PARAMETERS
       count     Number of blocks (integer)  also number of entries in arrays
                 array_of_types,  array_of_displacements, and
                 array_of_blocklengths.

       array_of_blocklengths
                 Number of elements in each block (array).

       array_of_displacements
                 Byte displacement of each block (array).

       array_of_types
                 Type of elements in each block (array of handles to datatype
                 objects).



OUTPUT PARAMETERS
       newtype   New datatype (handle).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       Note that use of this routine is deprecated as of MPI-2. Use
       MPI_Type_create_struct instead.

       This deprecated routine is not available in C++.

       MPI_Type_struct is the most general type constructor. It further
       generalizes MPI_Type_hindexed in that it allows each block to consist
       of replications of different datatypes.

       Example: Let type1 have type map

           {(double, 0), (char, 8)}

       with extent 16. Let B = (2, 1, 3), D = (0, 16, 26), and T = (MPI_FLOAT,
       type1, MPI_CHAR). Then a call to MPI_Type_struct(3, B, D, T, newtype)
       returns a datatype with type map

           {(float, 0), (float,4), (double, 16), (char, 24),
           (char, 26), (char, 27), (char, 28)}

       That is, two copies of MPI_FLOAT starting at 0, followed by one copy of
       type1 starting at 16, followed by three copies of MPI_CHAR, starting at
       26. (We assume that a float occupies 4 bytes.)

       For more information, see section 3.12.1 of the MPI-1.1 Standard.


NOTES
       If an upperbound is set explicitly by using the MPI datatype MPI_UB,
       the corresponding index must be positive.

       The MPI-1 Standard originally made vague statements about padding and
       alignment; this was intended to allow the simple definition of
       structures that could be sent with a count greater than one. For
       example,
           struct {int a; char b;} foo;
       may have
           sizeof(foo) = sizeof(int) + sizeof(char);
       defining the extent of a datatype as including an epsilon, which would
       have allowed an implementation to make the extent an MPI datatype for
       this structure equal to 2*sizeof(int). However, since different systems
       might define different paddings, a clarification to the standard made
       epsilon zero. Thus, if you define a structure datatype and wish to send
       or receive multiple items, you should explicitly include an MPI_UB
       entry as the last member of the structure.  For example, the following
       code can be used for the structure foo:

           blen[0] = 1; indices[0] = 0; oldtypes[0] = MPI_INT;
           blen[1] = 1; indices[1] = &foo.b - &foo; oldtypes[1] = MPI_CHAR;
           blen[2] = 1; indices[2] = sizeof(foo); oldtypes[2] = MPI_UB;
           MPI_Type_struct( 3, blen, indices, oldtypes, &newtype );



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.


SEE ALSO
       MPI_Type_create_struct
       MPI_Type_create_hindexed




1.4.1                            Jan 14, 2010               MPI_Type_struct(3)
