/*D
   MPI_T_cvar_get_num - Get the number of control variables

Synopsis:
.vb
int MPI_T_cvar_get_num(int *num_cvar)
.ve

Output Parameters:
. num_cvar - returns number of control variables (integer)

.N ThreadSafe

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

D*/

