Datatype(int size,MPI_Aint lb, MPI_Aint ub, int flags);
Datatype(char* name, int size,MPI_Aint lb, MPI_Aint ub, int flags);
Datatype(Datatype *datatype, int* ret);
Datatype(int size,MPI_Aint lb, MPI_Aint ub, int flags);
Datatype(char* name, int size,MPI_Aint lb, MPI_Aint ub, int flags);
Datatype(Datatype *datatype, int* ret);
static int create_indexed(int count, int* blocklens, int* indices, MPI_Datatype old_type, MPI_Datatype* new_type);
static int create_hindexed(int count, int* blocklens, MPI_Aint* indices, MPI_Datatype old_type, MPI_Datatype* new_type);
static int create_struct(int count, int* blocklens, MPI_Aint* indices, MPI_Datatype* old_types, MPI_Datatype* new_type);
static int create_indexed(int count, int* blocklens, int* indices, MPI_Datatype old_type, MPI_Datatype* new_type);
static int create_hindexed(int count, int* blocklens, MPI_Aint* indices, MPI_Datatype old_type, MPI_Datatype* new_type);
static int create_struct(int count, int* blocklens, MPI_Aint* indices, MPI_Datatype* old_types, MPI_Datatype* new_type);