dune

(executable (name test_rng) (libraries async mirage-crypto-rng-async) (preprocess (pps ppx_jane)))

test_rng.ml

open Core                                                                                 
open Async                                                                                
                                                                                          
let main () =
  let time_source = Synchronous_time_source.wall_clock () in                              
  let print_next_alarm_time () =
    let next_alarm_fires_in =
      Option.map                                                                          
        (Synchronous_time_source.next_alarm_fires_at time_source)                         
        ~f:(fun next -> Time_ns.diff next (Synchronous_time_source.now time_source))      
    in
    print_s [%message "" (next_alarm_fires_in : Time_ns.Span.t Option.t)];                
  in 
  print_next_alarm_time ();                                                               
  Mirage_crypto_rng_async.initialize ();                                                  
  print_next_alarm_time ();
  let rand = Mirage_crypto_rng.generate 8 in                                              
  let bs = Bigstring.sub ~pos:rand.off ~len:rand.len rand.buffer in                       
  print_endline (Bigstring.Hexdump.to_string_hum bs);                                     
  Synchronous_time_source.run_after                                                       
    time_source                                                                           
    (Time_ns.Span.of_int_sec 1) 
    (fun () -> 
      print_next_alarm_time ();
      Shutdown.shutdown 0)                                                                
;;  
    
let () = ignore (Scheduler.go_main ~main () : never_returns)