blocklength zero in MPI_Type_struct

[Peter Ganster <P.Ganster@magmasoft.de>]

Hello,

I have a question:

What happens if one use blocklenghts of zero in the call of
MPI_Type_struct: Is the behavior implementation dependent or is it
definded by the MPI-1 or MPI-2 standard?


Example:

 typedef struct {
   double a, b[2], c;
 } S;

 int count = 3;
 int blocklens[3] =  {0, 2, 0};
 MPI_Aint disps[3] = {0, offsetof(S, b), sizeof(S)}; 
 MPI_Datatype types[3] = {MPI_BYTE, MPI_DOUBLE, MPI_BYTE}; 
 MPI_Datatype newtype;

 MPI_Type_struct(count, blocklens, disps, types, &newtype);


And second, are there any technical standard papers (like the C language
standard paper of ANSI) that gives precise answers on questions like
above?



with kind regards
Peter Ganster