diff --git a/source/spawn/spawn-processes.ads b/source/spawn/spawn-processes.ads
index 42e12f2..5a5adf4 100644
--- a/source/spawn/spawn-processes.ads
+++ b/source/spawn/spawn-processes.ads
@@ -178,6 +178,48 @@ package Spawn.Processes is
       Data : out Ada.Streams.Stream_Element_Array;
       Last : out Ada.Streams.Stream_Element_Offset);
 
+   function Wait_For_Started
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean;
+   --  Block until process has started or until Timeout have passed. Return
+   --  True when process has been started successfully.
+   --
+   --  Started subprogram of the listener is called before exit from this
+   --  subprogram.
+
+   function Wait_For_Finished
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean;
+   --  Block until process has been finished ot until Timeout have passed.
+   --  Return True when process has finished.
+   --
+   --  Finished subprogram of the listener is called before exit from this
+   --  subprogram.
+
+   function Wait_For_Standard_Input_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean;
+   --  Block until standard input is available for write.
+   --
+   --  Standard_Input_Available subprogram of the listener is called before
+   --  exit from this subprogram.
+
+   function Wait_For_Standard_Output_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean;
+   --  Block until standard output has data available for read.
+   --
+   --  Standard_Output_Available subprogram of the listener is called before
+   --  exit from this subprogram.
+
+   function Wait_For_Standard_Error_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean;
+   --  Block until standard error has data available for read.
+   --
+   --  Standard_Error_Available subprogram of the listener is called before
+   --  exit from this subprogram.
+
 private
 
    use all type Internal.Pipe_Kinds;
diff --git a/source/spawn/spawn-processes__glib.adb b/source/spawn/spawn-processes__glib.adb
index 114210d..7f5b604 100644
--- a/source/spawn/spawn-processes__glib.adb
+++ b/source/spawn/spawn-processes__glib.adb
@@ -624,6 +624,66 @@ package body Spawn.Processes is
       pragma Assert (Code = 0);
    end Terminate_Process;
 
+   -----------------------
+   -- Wait_For_Finished --
+   -----------------------
+
+   function Wait_For_Finished
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Finished;
+
+   ---------------------------------------
+   -- Wait_For_Standard_Error_Available --
+   ---------------------------------------
+
+   function Wait_For_Standard_Error_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Error_Available;
+
+   ---------------------------------------
+   -- Wait_For_Standard_Input_Available --
+   ---------------------------------------
+
+   function Wait_For_Standard_Input_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Input_Available;
+
+   ----------------------------------------
+   -- Wait_For_Standard_Output_Available --
+   ----------------------------------------
+
+   function Wait_For_Standard_Output_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Output_Available;
+
+   ----------------------
+   -- Wait_For_Started --
+   ----------------------
+
+   function Wait_For_Started
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Started;
+
    -----------------------
    -- Working_Directory --
    -----------------------
diff --git a/source/spawn/spawn-processes__glib_windows.adb b/source/spawn/spawn-processes__glib_windows.adb
index f850b9a..dad1e93 100644
--- a/source/spawn/spawn-processes__glib_windows.adb
+++ b/source/spawn/spawn-processes__glib_windows.adb
@@ -403,6 +403,66 @@ package body Spawn.Processes is
       Windows.Do_Terminate_Process (Self);
    end Terminate_Process;
 
+   -----------------------
+   -- Wait_For_Finished --
+   -----------------------
+
+   function Wait_For_Finished
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Finished;
+
+   ---------------------------------------
+   -- Wait_For_Standard_Error_Available --
+   ---------------------------------------
+
+   function Wait_For_Standard_Error_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Error_Available;
+
+   ---------------------------------------
+   -- Wait_For_Standard_Input_Available --
+   ---------------------------------------
+
+   function Wait_For_Standard_Input_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Input_Available;
+
+   ----------------------------------------
+   -- Wait_For_Standard_Output_Available --
+   ----------------------------------------
+
+   function Wait_For_Standard_Output_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Output_Available;
+
+   ----------------------
+   -- Wait_For_Started --
+   ----------------------
+
+   function Wait_For_Started
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Started;
+
    -----------------------
    -- Working_Directory --
    -----------------------
diff --git a/source/spawn/spawn-processes__posix.adb b/source/spawn/spawn-processes__posix.adb
index 426e704..f02c94a 100644
--- a/source/spawn/spawn-processes__posix.adb
+++ b/source/spawn/spawn-processes__posix.adb
@@ -312,6 +312,66 @@ package body Spawn.Processes is
       pragma Assert (Code = 0);
    end Terminate_Process;
 
+   -----------------------
+   -- Wait_For_Finished --
+   -----------------------
+
+   function Wait_For_Finished
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Finished;
+
+   ---------------------------------------
+   -- Wait_For_Standard_Error_Available --
+   ---------------------------------------
+
+   function Wait_For_Standard_Error_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Error_Available;
+
+   ---------------------------------------
+   -- Wait_For_Standard_Input_Available --
+   ---------------------------------------
+
+   function Wait_For_Standard_Input_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Input_Available;
+
+   ----------------------------------------
+   -- Wait_For_Standard_Output_Available --
+   ----------------------------------------
+
+   function Wait_For_Standard_Output_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Output_Available;
+
+   ----------------------
+   -- Wait_For_Started --
+   ----------------------
+
+   function Wait_For_Started
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Started;
+
    -----------------------
    -- Working_Directory --
    -----------------------
diff --git a/source/spawn/spawn-processes__windows.adb b/source/spawn/spawn-processes__windows.adb
index 978d19b..da64cec 100644
--- a/source/spawn/spawn-processes__windows.adb
+++ b/source/spawn/spawn-processes__windows.adb
@@ -263,6 +263,66 @@ package body Spawn.Processes is
       Windows.Do_Terminate_Process (Self);
    end Terminate_Process;
 
+   -----------------------
+   -- Wait_For_Finished --
+   -----------------------
+
+   function Wait_For_Finished
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Finished;
+
+   ---------------------------------------
+   -- Wait_For_Standard_Error_Available --
+   ---------------------------------------
+
+   function Wait_For_Standard_Error_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Error_Available;
+
+   ---------------------------------------
+   -- Wait_For_Standard_Input_Available --
+   ---------------------------------------
+
+   function Wait_For_Standard_Input_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Input_Available;
+
+   ----------------------------------------
+   -- Wait_For_Standard_Output_Available --
+   ----------------------------------------
+
+   function Wait_For_Standard_Output_Available
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Standard_Output_Available;
+
+   ----------------------
+   -- Wait_For_Started --
+   ----------------------
+
+   function Wait_For_Started
+     (Self    : in out Process'Class;
+      Timeout : Duration := Duration'Last) return Boolean is
+   begin
+      raise Program_Error;
+      return False;
+   end Wait_For_Started;
+
    -----------------------
    -- Working_Directory --
    -----------------------