/*D
   MPI_T_category_get_cvars - Get control variables in a category

Synopsis:
.vb
int MPI_T_category_get_cvars(int cat_index, int len, int indices[])
.ve

Input Parameters:
+ cat_index - index of the category to be queried, in the range $0$ and $num_cat-1$ (integer)
- len - the length of the indices array (integer)

Output Parameters:
. indices - an integer array of size len, indicating control variable indices (integer)

.N ThreadSafe

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

D*/

