/*D
   MPI_Unpack_external - Unpack a buffer (packed with MPI_Pack_external) according to a datatype into contiguous memory

Synopsis:
.vb
int MPI_Unpack_external(const char datarep[], const void *inbuf,
                        MPI_Aint insize, MPI_Aint *position, void *outbuf,
                        int outcount, MPI_Datatype datatype)
.ve
.vb
int MPI_Unpack_external_c(const char datarep[], const void *inbuf,
                          MPI_Count insize, MPI_Count *position, void *outbuf,
                          MPI_Count outcount, MPI_Datatype datatype)
.ve

Input Parameters:
+ datarep - data representation (string)
. inbuf - input buffer start (choice)
. insize - input buffer size, in bytes (integer)
. outcount - number of output data items (integer)
- datatype - datatype of output data item (handle)

Input/Output Parameters:
. position - current position in buffer, in bytes (integer)

Output Parameters:
. outbuf - output buffer start (choice)

.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*/

