Allow a block indexed type with a count of zero. Be user friendly and set the ub, lb,

true_lb as well as the true_ub to zero in this case.

This commit was SVN r10208.

ompi/datatype/dt_create_indexed.c

@@ -100,7 +100,10 @@ int32_t ompi_ddt_create_indexed_block( int count, int bLength, const int* pDisp,
 
    if( (count == 0) || (bLength == 0) ) {
       *newType = ompi_ddt_create(1);
-      ompi_ddt_add( *newType, oldType, 0, pDisp[0] * extent, extent );
+      if( 0 == count )
+          ompi_ddt_add( *newType, &ompi_mpi_datatype_null, 0, 0, 0 );
+      else
+          ompi_ddt_add( *newType, oldType, 0, pDisp[0] * extent, extent );
       return OMPI_SUCCESS;
    }
    pdt = ompi_ddt_create( count * (2 + oldType->desc.used) );

ompi/mpi/c/type_create_indexed_block.c

@@ -45,7 +45,7 @@ int MPI_Type_create_indexed_block(int count,
       if( count < 0 ) {
         return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_COUNT, 
                                       FUNC_NAME);
-      } else if( blocklength < 0 || NULL == array_of_displacements) {
+      } else if( (count > 0) && (blocklength < 0 || NULL == array_of_displacements) ) {
         return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, MPI_ERR_ARG,
                                       FUNC_NAME );
       } else if (NULL == oldtype || MPI_DATATYPE_NULL == oldtype ||