/*D
   MPI_T_cvar_write - Write a control variable

Synopsis:
.vb
int MPI_T_cvar_write(MPI_T_cvar_handle handle, const void *buf)
.ve

Input Parameters:
+ handle - handle to the control variable to be written (handle)
- buf - initial address of storage location for variable value (choice)

.N ThreadSafe

.N Errors
.N MPI_SUCCESS
.N MPI_T_ERR_CVAR_SET_NEVER
.N MPI_T_ERR_CVAR_SET_NOT_NOW
.N MPI_T_ERR_INVALID
.N MPI_T_ERR_INVALID_HANDLE
.N MPI_T_ERR_NOT_INITIALIZED
.N MPI_ERR_OTHER

D*/

