diff --git a/src/driver/call_provers.ml b/src/driver/call_provers.ml
index 388572b8c04b69c8d47657d15717c4b3c8c7fb22..9ffcd20c2d981dccfb24f7ee3ccf00f2c9c78dc8 100644
--- a/src/driver/call_provers.ml
+++ b/src/driver/call_provers.ml
@@ -359,6 +359,7 @@ let call_on_file ~command ~limit ~res_parser ~printer_mapping
   Hashtbl.add saved_data id save;
   let timelimit = get_time limit in
   let memlimit = get_mem limit in
+  let use_stdin = if use_stdin then Some fin else None in
   Prove_client.send_request ~use_stdin ~id ~timelimit ~memlimit ~cmd;
   ServerCall id
 
diff --git a/src/driver/prove_client.ml b/src/driver/prove_client.ml
index 7e530d4230e1fd5eae123c7bcfddd115805c8888..2588c4ea4514aac57c2b5b32defe1ee23ee52a02 100644
--- a/src/driver/prove_client.ml
+++ b/src/driver/prove_client.ml
@@ -95,7 +95,7 @@ let set_max_running_provers x =
 let send_request ~use_stdin ~id ~timelimit ~memlimit ~cmd =
   force_connect ();
   let buf = Buffer.create 128 in
-  let servercommand = if use_stdin then "runstdin;" else "run;" in
+  let servercommand = if use_stdin <> None then "runstdin;" else "run;" in
   Buffer.add_string buf servercommand;
   Buffer.add_string buf (string_of_int id);
   Buffer.add_char buf ';';
@@ -106,6 +106,12 @@ let send_request ~use_stdin ~id ~timelimit ~memlimit ~cmd =
       Buffer.add_char buf ';';
       Buffer.add_string buf x)
     cmd;
+  begin match use_stdin with
+  | None -> ()
+  | Some s ->
+      Buffer.add_char buf ';';
+      Buffer.add_string buf s
+  end;
   Buffer.add_char buf '\n';
   let s = Buffer.contents buf in
   send_request_string s
diff --git a/src/driver/prove_client.mli b/src/driver/prove_client.mli
index d7a14a73c09c1e7a6f032789fd2e2d32c2dbdb1e..0182b8bbbbab4fbc3606e668a3b576c58b94859f 100644
--- a/src/driver/prove_client.mli
+++ b/src/driver/prove_client.mli
@@ -6,7 +6,7 @@ val set_max_running_provers : int -> unit
 val connect : unit -> unit
 
 val send_request :
- use_stdin:bool ->
+ use_stdin:string option ->
  id:int ->
  timelimit:int ->
  memlimit:int ->
diff --git a/src/server/server-unix.c b/src/server/server-unix.c
index 21ac85ba214aebbcadd7b021bb21cded29442a77..6e86e7309f0c48a33bfd4bf1af35dda9513f15fd 100644
--- a/src/server/server-unix.c
+++ b/src/server/server-unix.c
@@ -257,7 +257,7 @@ pid_t create_process(char* cmd,
   unix_argv = (char**)malloc(sizeof(char*) * (argc + 2));
   unix_argv[0] = cmd;
   unix_argv[argc + 1] = NULL;
-  for (i = 0; i < argc; i++) {
+  for (i = 0; i < count; i++) {
     unix_argv[i + 1] = argv[i];
   }