NAME

       MPI_Type_struct -  Creates a struct datatype

SYNOPSIS

       int MPI_Type_struct(int count,
                          int *array_of_blocklengths,
                          MPI_Aint *array_of_displacements,
                          MPI_Datatype *array_of_types,
                          MPI_Datatype *newtype)

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)

DEPRECATED FUNCTION

       The MPI-2 standard deprecated a number of routines because MPI-2 provides better versions.
       This  routine  is  one of those that was deprecated.  The routine may continue to be used,
       but new code should use the replacement routine.  The  replacement  for  this  routine  is
       MPI_Type_create_struct

NOTES

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

       The MPI standard originally made vague statements about padding and  alignment;  this  was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)  ;  for  example,  sizeof(foo)  ==
       2*sizeof(int)  .  The initial version of the MPI standard defined the extent of a datatype
       as including an epsilon that 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,  there  was  much
       discussion by the MPI Forum  about  what  was  the  correct  value  of  epsilon,  and  one
       suggestion  was  to  define epsilon as zero.  This would have been the best thing to do in
       MPI 1.0, particularly since the MPI_UB type allows the user to easily set the end  of  the
       structure.   Unfortunately,  this  change  did  not  make  it  into  the  final  document.
       Currently, this routine does not add any padding, since the amount of  padding  needed  is
       determined  by  the  compiler that the user is using to build their code, not the compiler
       used to construct the MPI library.  A later version of MPICH may provide for some  natural
       choices of padding (e.g., multiple of the size of the largest basic member), but users are
       advised to never depend on this, even with vendor MPI implementations.   Instead,  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; array_of_displacements[0] = 0; oldtypes[0] = MPI_INT;
       blen[1] = 1; array_of_displacements[1] = &foo.b - &foo; oldtypes[1] = MPI_CHAR;
       blen[2] = 1; array_of_displacements[2] = sizeof(foo); oldtypes[2] = MPI_UB;
       MPI_Type_struct( 3, blen, array_of_displacements, oldtypes, &newtype );

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_TYPE
              -  Invalid datatype argument.  Additionally, this error can occur if an uncommitted
              MPI_Datatype (see MPI_Type_commit ) is used in a communication call.
       MPI_ERR_COUNT
              - Invalid count argument.  Count arguments must be non-negative; a count of zero is
              often valid.
       MPI_ERR_INTERN
              -  This  error  is returned when some part of the MPICH implementation is unable to
              acquire memory.

                                            11/12/2016                         MPI_Type_struct(3)