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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- G N A T . E X P E C T . N O N _ B L O C K I N G _ S P A W N --
-- --
-- B o d y --
-- --
-- Copyright (C) 2005-2008, AdaCore --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This package provides a target dependent non-blocking spawn function
-- for use by the VMS GNAT.Expect package (g-expect-vms.adb). This package
-- should not be directly with'ed by an application program.
-- This version is for Alpha/VMS
separate (GNAT.Expect)
procedure Non_Blocking_Spawn
(Descriptor : out Process_Descriptor'Class;
Command : String;
Args : GNAT.OS_Lib.Argument_List;
Buffer_Size : Natural := 4096;
Err_To_Out : Boolean := False)
is
function Alloc_Vfork_Blocks return Integer;
pragma Import (C, Alloc_Vfork_Blocks, "decc$$alloc_vfork_blocks");
function Get_Vfork_Jmpbuf return System.Address;
pragma Import (C, Get_Vfork_Jmpbuf, "decc$$get_vfork_jmpbuf");
function Get_Current_Invo_Context
(Addr : System.Address) return Process_Id;
pragma Import (C, Get_Current_Invo_Context,
"LIB$GET_CURRENT_INVO_CONTEXT");
Pipe1, Pipe2, Pipe3 : aliased Pipe_Type;
Arg : String_Access;
Arg_List : aliased array (1 .. Args'Length + 2) of System.Address;
Command_With_Path : String_Access;
begin
-- Create the rest of the pipes
Set_Up_Communications
(Descriptor, Err_To_Out, Pipe1'Access, Pipe2'Access, Pipe3'Access);
Command_With_Path := Locate_Exec_On_Path (Command);
if Command_With_Path = null then
raise Invalid_Process;
end if;
-- Fork a new process (it is not possible to do this in a subprogram)
if Alloc_Vfork_Blocks >= 0 then
Descriptor.Pid := Get_Current_Invo_Context (Get_Vfork_Jmpbuf);
else
Descriptor.Pid := -1;
end if;
-- Are we now in the child
if Descriptor.Pid = Null_Pid then
-- Prepare an array of arguments to pass to C
Arg := new String (1 .. Command_With_Path'Length + 1);
Arg (1 .. Command_With_Path'Length) := Command_With_Path.all;
Arg (Arg'Last) := ASCII.NUL;
Arg_List (1) := Arg.all'Address;
for J in Args'Range loop
Arg := new String (1 .. Args (J)'Length + 1);
Arg (1 .. Args (J)'Length) := Args (J).all;
Arg (Arg'Last) := ASCII.NUL;
Arg_List (J + 2 - Args'First) := Arg.all'Address;
end loop;
Arg_List (Arg_List'Last) := System.Null_Address;
-- This does not return on Unix systems
Set_Up_Child_Communications
(Descriptor, Pipe1, Pipe2, Pipe3, Command_With_Path.all,
Arg_List'Address);
end if;
Free (Command_With_Path);
-- Did we have an error when spawning the child ?
if Descriptor.Pid < Null_Pid then
raise Invalid_Process;
else
-- We are now in the parent process
Set_Up_Parent_Communications (Descriptor, Pipe1, Pipe2, Pipe3);
end if;
-- Create the buffer
Descriptor.Buffer_Size := Buffer_Size;
if Buffer_Size /= 0 then
Descriptor.Buffer := new String (1 .. Positive (Buffer_Size));
end if;
end Non_Blocking_Spawn;
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