/*D
   MPI_Pack_external_size - Returns the upper bound on the amount of space needed to pack a message using MPI_Pack_external.

Synopsis:
.vb
int MPI_Pack_external_size(const char *datarep, int incount,
                           MPI_Datatype datatype, MPI_Aint *size)
.ve
.vb
int MPI_Pack_external_size_c(const char *datarep, MPI_Count incount,
                             MPI_Datatype datatype, MPI_Count *size)
.ve

Input Parameters:
+ datarep - data representation (string)
. incount - number of input data items (integer)
- datatype - datatype of each input data item (handle)

Output Parameters:
. size - output buffer size, in bytes (integer)

.N ThreadSafe

.N Fortran

.N Errors
.N MPI_SUCCESS
.N MPI_ERR_ARG
.N MPI_ERR_COUNT
.N MPI_ERR_TYPE
.N MPI_ERR_OTHER

D*/

