/*D
   MPI_T_category_get_num - Get the number of categories

Synopsis:
.vb
int MPI_T_category_get_num(int *num_cat)
.ve

Output Parameters:
. num_cat - current number of categories (integer)

.N ThreadSafe

.N Errors
.N MPI_SUCCESS
.N MPI_T_ERR_INVALID
.N MPI_T_ERR_NOT_INITIALIZED
.N MPI_ERR_OTHER

D*/

