/*D
   MPIX_Threadcomm_start - start/activiate a thread communicator (inside thread parallel regions)

Synopsis:
.vb
int MPIX_Threadcomm_start(MPI_Comm threadcomm)
.ve

Input Parameters:
. threadcomm - thread communicator (handle)

.N ThreadSafe

.N Fortran

.N Errors
.N MPI_SUCCESS
.N MPI_ERR_COMM
.N MPI_ERR_OTHER

.seealso: MPIX_Threadcomm_init, MPIX_Threadcomm_finish, MPIX_Threadcomm_free
D*/

