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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                        S Y S T E M . O S _ L I B                         --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 1995-2012, Free Software Foundation, Inc.         --

--                                                                          --

-- 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 3,  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.                                     --

--                                                                          --

-- As a special exception under Section 7 of GPL version 3, you are granted --

-- additional permissions described in the GCC Runtime Library Exception,   --

-- version 3.1, as published by the Free Software Foundation.               --

--                                                                          --

-- You should have received a copy of the GNU General Public License and    --

-- a copy of the GCC Runtime Library Exception along with this program;     --

-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --

-- <http://www.gnu.org/licenses/>.                                          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

--  Operating system interface facilities

--  This package contains types and procedures for interfacing to the

--  underlying OS. It is used by the GNAT compiler and by tools associated

--  with the GNAT compiler, and therefore works for the various operating

--  systems to which GNAT has been ported. This package will undoubtedly grow

--  as new services are needed by various tools.

--  This package tends to use fairly low-level Ada in order to not bring in

--  large portions of the RTL. For example, functions return access to string

--  as part of avoiding functions returning unconstrained types.

--  Except where specifically noted, these routines are portable across all

--  GNAT implementations on all supported operating systems.

--  Note: this package is in the System hierarchy so that it can be directly

--  be used by other predefined packages. User access to this package is via

--  a renaming of this package in GNAT.OS_Lib (file g-os_lib.ads).

pragma Compiler_Unit;

with System;

with System.Strings;

package System.OS_Lib is

   pragma Elaborate_Body (OS_Lib);

   -----------------------

   -- String Operations --

   -----------------------

   --  These are reexported from package Strings (which was introduced to

   --  avoid different packages declaring different types unnecessarily).

   --  See package System.Strings for details.

   subtype String_Access is Strings.String_Access;

   function "=" (Left, Right : String_Access) return Boolean

     renames Strings."=";

   procedure Free (X : in out String_Access) renames Strings.Free;

   subtype String_List is Strings.String_List;

   function "=" (Left, Right : String_List) return Boolean

     renames Strings."=";

   function "&" (Left : String_Access; Right : String_Access)

     return String_List renames Strings."&";

   function "&" (Left : String_Access; Right : String_List)

     return String_List renames Strings."&";

   function "&" (Left : String_List; Right : String_Access)

     return String_List renames Strings."&";

   function "&" (Left : String_List; Right : String_List)

     return String_List renames Strings."&";

   subtype String_List_Access is Strings.String_List_Access;

   function "=" (Left, Right : String_List_Access) return Boolean

     renames Strings."=";

   procedure Free (Arg : in out String_List_Access)

     renames Strings.Free;

   ---------------------

   -- Time/Date Stuff --

   ---------------------

   type OS_Time is private;

   --  The OS's notion of time is represented by the private type OS_Time.

   --  This is the type returned by the File_Time_Stamp functions to obtain

   --  the time stamp of a specified file. Functions and a procedure (modeled

   --  after the similar subprograms in package Calendar) are provided for

   --  extracting information from a value of this type. Although these are

   --  called GM, the intention is not that they provide GMT times in all

   --  cases but rather the actual (time-zone independent) time stamp of the

   --  file (of course in Unix systems, this *is* in GMT form).

   Invalid_Time : constant OS_Time;

   --  A special unique value used to flag an invalid time stamp value

   subtype Year_Type   is Integer range 1900 .. 2099;

   subtype Month_Type  is Integer range    1 ..   12;

   subtype Day_Type    is Integer range    1 ..   31;

   subtype Hour_Type   is Integer range    0 ..   23;

   subtype Minute_Type is Integer range    0 ..   59;

   subtype Second_Type is Integer range    0 ..   59;

   --  Declarations similar to those in Calendar, breaking down the time

   function Current_Time return OS_Time;

   --  Return the system clock value as OS_Time

   function GM_Year    (Date : OS_Time) return Year_Type;

   function GM_Month   (Date : OS_Time) return Month_Type;

   function GM_Day     (Date : OS_Time) return Day_Type;

   function GM_Hour    (Date : OS_Time) return Hour_Type;

   function GM_Minute  (Date : OS_Time) return Minute_Type;

   function GM_Second  (Date : OS_Time) return Second_Type;

   --  Functions to extract information from OS_Time value

   function "<"  (X, Y : OS_Time) return Boolean;

   function ">"  (X, Y : OS_Time) return Boolean;

   function ">=" (X, Y : OS_Time) return Boolean;

   function "<=" (X, Y : OS_Time) return Boolean;

   --  Basic comparison operators on OS_Time with obvious meanings. Note that

   --  these have Intrinsic convention, so for example it is not permissible

   --  to create accesses to any of these functions.

   procedure GM_Split

     (Date   : OS_Time;

      Year   : out Year_Type;

      Month  : out Month_Type;

      Day    : out Day_Type;

      Hour   : out Hour_Type;

      Minute : out Minute_Type;

      Second : out Second_Type);

   --  Analogous to the Split routine in Ada.Calendar, takes an OS_Time and

   --  provides a representation of it as a set of component parts, to be

   --  interpreted as a date point in UTC.

   ----------------

   -- File Stuff --

   ----------------

   --  These routines give access to the open/creat/close/read/write level of

   --  I/O routines in the typical C library (these functions are not part of

   --  the ANSI C standard, but are typically available in all systems). See

   --  also package Interfaces.C_Streams for access to the stream level

   --  routines.

   --  Note on file names. If a file name is passed as type String in any of

   --  the following specifications, then the name is a normal Ada string and

   --  need not be NUL-terminated. However, a trailing NUL character is

   --  permitted, and will be ignored (more accurately, the NUL and any

   --  characters that follow it will be ignored).

   type File_Descriptor is new Integer;

   --  Corresponds to the int file handle values used in the C routines

   Standin  : constant File_Descriptor := 0;

   Standout : constant File_Descriptor := 1;

   Standerr : constant File_Descriptor := 2;

   --  File descriptors for standard input output files

   Invalid_FD : constant File_Descriptor := -1;

   --  File descriptor returned when error in opening/creating file

   type Mode is (Binary, Text);

   for Mode'Size use Integer'Size;

   for Mode use (Binary => 0, Text => 1);

   --  Used in all the Open and Create calls to specify if the file is to be

   --  opened in binary mode or text mode. In systems like Unix, this has no

   --  effect, but in systems capable of text mode translation, the use of

   --  Text as the mode parameter causes the system to do CR/LF translation

   --  and also to recognize the DOS end of file character on input. The use

   --  of Text where appropriate allows programs to take a portable Unix view

   --  of DOS-format files and process them appropriately.

   function Open_Read

     (Name  : String;

      Fmode : Mode) return File_Descriptor;

   --  Open file Name for reading, returning file descriptor File descriptor

   --  returned is Invalid_FD if file cannot be opened.

   function Open_Read_Write

     (Name  : String;

      Fmode : Mode) return File_Descriptor;

   --  Open file Name for both reading and writing, returning file descriptor.

   --  File descriptor returned is Invalid_FD if file cannot be opened.

   function Create_File

     (Name  : String;

      Fmode : Mode) return File_Descriptor;

   --  Creates new file with given name for writing, returning file descriptor

   --  for subsequent use in Write calls. If the file already exists, it is

   --  overwritten. File descriptor returned is Invalid_FD if file cannot be

   --  successfully created.

   function Create_Output_Text_File (Name : String) return File_Descriptor;

   --  Creates new text file with given name suitable to redirect standard

   --  output, returning file descriptor. File descriptor returned is

   --  Invalid_FD if file cannot be successfully created.

   function Create_New_File

     (Name  : String;

      Fmode : Mode) return File_Descriptor;

   --  Create new file with given name for writing, returning file descriptor

   --  for subsequent use in Write calls. This differs from Create_File in

   --  that it fails if the file already exists. File descriptor returned is

   --  Invalid_FD if the file exists or cannot be created.

   Temp_File_Len : constant Integer := 12;

   --  Length of name returned by Create_Temp_File call (GNAT-XXXXXX & NUL)

   subtype Temp_File_Name is String (1 .. Temp_File_Len);

   --  String subtype set by Create_Temp_File

   procedure Create_Temp_File

     (FD   : out File_Descriptor;

      Name : out Temp_File_Name);

   --  Create and open for writing a temporary file in the current working

   --  directory. The name of the file and the File Descriptor are returned.

   --  The File Descriptor returned is Invalid_FD in the case of failure. No

   --  mode parameter is provided. Since this is a temporary file, there is no

   --  point in doing text translation on it.

   --

   --  On some operating systems, the maximum number of temp files that can be

   --  created with this procedure may be limited. When the maximum is reached,

   --  this procedure returns Invalid_FD. On some operating systems, there may

   --  be a race condition between processes trying to create temp files at the

   --  same time in the same directory using this procedure.

   procedure Create_Temp_File

     (FD   : out File_Descriptor;

      Name : out String_Access);

   --  Create and open for writing a temporary file in the current working

   --  directory. The name of the file and the File Descriptor are returned.

   --  It is the responsibility of the caller to deallocate the access value

   --  returned in Name.

   --

   --  The file is opened in binary mode (no text translation).

   --

   --  This procedure will always succeed if the current working directory is

   --  writable. If the current working directory is not writable, then

   --  Invalid_FD is returned for the file descriptor and null for the Name.

   --  There is no race condition problem between processes trying to create

   --  temp files at the same time in the same directory.

   procedure Create_Temp_Output_File

     (FD   : out File_Descriptor;

      Name : out String_Access);

   --  Create and open for writing a temporary file in the current working

   --  directory suitable to redirect standard output. The name of the file and

   --  the File Descriptor are returned. It is the responsibility of the caller

   --  to deallocate the access value returned in Name.

   --

   --  The file is opened in text mode

   --

   --  This procedure will always succeed if the current working directory is

   --  writable. If the current working directory is not writable, then

   --  Invalid_FD is returned for the file descriptor and null for the Name.

   --  There is no race condition problem between processes trying to create

   --  temp files at the same time in the same directory.

   procedure Close (FD : File_Descriptor; Status : out Boolean);

   --  Close file referenced by FD. Status is False if the underlying service

   --  failed. Reasons for failure include: disk full, disk quotas exceeded

   --  and invalid file descriptor (the file may have been closed twice).

   procedure Close (FD : File_Descriptor);

   --  Close file referenced by FD. This form is used when the caller wants to

   --  ignore any possible error (see above for error cases).

   procedure Set_Close_On_Exec

     (FD            : File_Descriptor;

      Close_On_Exec : Boolean;

      Status        : out Boolean);

   --  When Close_On_Exec is True, mark FD to be closed automatically when new

   --  program is executed by the calling process (i.e. prevent FD from being

   --  inherited by child processes). When Close_On_Exec is False, mark FD to

   --  not be closed on exec (i.e. allow it to be inherited). Status is False

   --  if the operation could not be performed.

   procedure Delete_File (Name : String; Success : out Boolean);

   --  Deletes file. Success is set True or False indicating if the delete is

   --  successful.

   procedure Rename_File

     (Old_Name : String;

      New_Name : String;

      Success  : out Boolean);

   --  Rename a file. Success is set True or False indicating if the rename is

   --  successful or not.

   --  The following defines the mode for the Copy_File procedure below. Note

   --  that "time stamps and other file attributes" in the descriptions below

   --  refers to the creation and last modification times, and also the file

   --  access (read/write/execute) status flags.

   type Copy_Mode is

     (Copy,

      --  Copy the file. It is an error if the target file already exists. The

      --  time stamps and other file attributes are preserved in the copy.

      Overwrite,

      --  If the target file exists, the file is replaced otherwise the file

      --  is just copied. The time stamps and other file attributes are

      --  preserved in the copy.

      Append);

      --  If the target file exists, the contents of the source file is

      --  appended at the end. Otherwise the source file is just copied. The

      --  time stamps and other file attributes are preserved if the

      --  destination file does not exist.

   type Attribute is

     (Time_Stamps,

      --  Copy time stamps from source file to target file. All other

      --  attributes are set to normal default values for file creation.

      Full,

      --  All attributes are copied from the source file to the target file.

      --  This includes the timestamps, and for example also includes

      --  read/write/execute attributes in Unix systems.

      None);

      --  No attributes are copied. All attributes including the time stamp

      --  values are set to normal default values for file creation.

   --  Note: The default is Time_Stamps, which corresponds to the normal

   --  default on Windows style systems. Full corresponds to the typical

   --  effect of "cp -p" on Unix systems, and None corresponds to the typical

   --  effect of "cp" on Unix systems.

   --  Note: Time_Stamps and Full are not supported on VMS and VxWorks 5

   procedure Copy_File

     (Name     : String;

      Pathname : String;

      Success  : out Boolean;

      Mode     : Copy_Mode := Copy;

      Preserve : Attribute := Time_Stamps);

   --  Copy a file. Name must designate a single file (no wild cards allowed).

   --  Pathname can be a filename or directory name. In the latter case Name

   --  is copied into the directory preserving the same file name. Mode

   --  defines the kind of copy, see above with the default being a normal

   --  copy in which the target file must not already exist. Success is set to

   --  True or False indicating if the copy is successful (depending on the

   --  specified Mode).

   --

   --  Note: this procedure is only supported to a very limited extent on VMS.

   --  The only supported mode is Overwrite, and the only supported value for

   --  Preserve is None, resulting in the default action which for Overwrite

   --  is to leave attributes unchanged. Furthermore, the copy only works for

   --  simple text files.

   procedure Copy_Time_Stamps (Source, Dest : String; Success : out Boolean);

   --  Copy Source file time stamps (last modification and last access time

   --  stamps) to Dest file. Source and Dest must be valid filenames,

   --  furthermore Dest must be writable. Success will be set to True if the

   --  operation was successful and False otherwise.

   --

   --  Note: this procedure is not supported on VMS and VxWorks 5. On these

   --  platforms, Success is always set to False.

   function Read

     (FD : File_Descriptor;

      A  : System.Address;

      N  : Integer) return Integer;

   --  Read N bytes to address A from file referenced by FD. Returned value is

   --  count of bytes actually read, which can be less than N at EOF.

   function Write

     (FD : File_Descriptor;

      A  : System.Address;

      N  : Integer) return Integer;

   --  Write N bytes from address A to file referenced by FD. The returned

   --  value is the number of bytes written, which can be less than N if a

   --  disk full condition was detected.

   Seek_Cur : constant := 1;

   Seek_End : constant := 2;

   Seek_Set : constant := 0;

   --  Used to indicate origin for Lseek call

   procedure Lseek

     (FD     : File_Descriptor;

      offset : Long_Integer;

      origin : Integer);

   pragma Import (C, Lseek, "__gnat_lseek");

   --  Sets the current file pointer to the indicated offset value, relative

   --  to the current position (origin = SEEK_CUR), end of file (origin =

   --  SEEK_END), or start of file (origin = SEEK_SET).

   function File_Length (FD : File_Descriptor) return Long_Integer;

   pragma Import (C, File_Length, "__gnat_file_length");

   --  Get length of file from file descriptor FD

   function File_Time_Stamp (Name : String) return OS_Time;

   --  Given the name of a file or directory, Name, obtains and returns the

   --  time stamp. This function can be used for an unopened file. Returns

   --  Invalid_Time is Name doesn't correspond to an existing file.

   function File_Time_Stamp (FD : File_Descriptor) return OS_Time;

   --  Get time stamp of file from file descriptor FD Returns Invalid_Time is

   --  FD doesn't correspond to an existing file.

   function Normalize_Pathname

     (Name           : String;

      Directory      : String  := "";

      Resolve_Links  : Boolean := True;

      Case_Sensitive : Boolean := True) return String;

   --  Returns a file name as an absolute path name, resolving all relative

   --  directories, and symbolic links. The parameter Directory is a fully

   --  resolved path name for a directory, or the empty string (the default).

   --  Name is the name of a file, which is either relative to the given

   --  directory name, if Directory is non-null, or to the current working

   --  directory if Directory is null. The result returned is the normalized

   --  name of the file. For most cases, if two file names designate the same

   --  file through different paths, Normalize_Pathname will return the same

   --  canonical name in both cases. However, there are cases when this is not

   --  true; for example, this is not true in Unix for two hard links

   --  designating the same file.

   --

   --  On Windows, the returned path will start with a drive letter except

   --  when Directory is not empty and does not include a drive letter. If

   --  Directory is empty (the default) and Name is a relative path or an

   --  absolute path without drive letter, the letter of the current drive

   --  will start the returned path. If Case_Sensitive is True (the default),

   --  then this drive letter will be forced to upper case ("C:\...").

   --

   --  If Resolve_Links is set to True, then the symbolic links, on systems

   --  that support them, will be fully converted to the name of the file or

   --  directory pointed to. This is slightly less efficient, since it

   --  requires system calls.

   --

   --  If Name cannot be resolved or is null on entry (for example if there is

   --  symbolic link circularity, e.g. A is a symbolic link for B, and B is a

   --  symbolic link for A), then Normalize_Pathname returns an empty  string.

   --

   --  In VMS, if Name follows the VMS syntax file specification, it is first

   --  converted into Unix syntax. If the conversion fails, Normalize_Pathname

   --  returns an empty string.

   --

   --  For case-sensitive file systems, the value of Case_Sensitive parameter

   --  is ignored. For file systems that are not case-sensitive, such as

   --  Windows and OpenVMS, if this parameter is set to False, then the file

   --  and directory names are folded to lower case. This allows checking

   --  whether two files are the same by applying this function to their names

   --  and comparing the results. If Case_Sensitive is set to True, this

   --  function does not change the casing of file and directory names.

   function Is_Absolute_Path (Name : String) return Boolean;

   --  Returns True if Name is an absolute path name, i.e. it designates a

   --  file or directory absolutely rather than relative to another directory.

   function Is_Regular_File (Name : String) return Boolean;

   --  Determines if the given string, Name, is the name of an existing

   --  regular file. Returns True if so, False otherwise. Name may be an

   --  absolute path name or a relative path name, including a simple file

   --  name. If it is a relative path name, it is relative to the current

   --  working directory.

   function Is_Directory (Name : String) return Boolean;

   --  Determines if the given string, Name, is the name of a directory.

   --  Returns True if so, False otherwise. Name may be an absolute path

   --  name or a relative path name, including a simple file name. If it is

   --  a relative path name, it is relative to the current working directory.

   function Is_Readable_File (Name : String) return Boolean;

   --  Determines if the given string, Name, is the name of an existing file

   --  that is readable. Returns True if so, False otherwise. Note that this

   --  function simply interrogates the file attributes (e.g. using the C

   --  function stat), so it does not indicate a situation in which a file may

   --  not actually be readable due to some other process having exclusive

   --  access.

   function Is_Executable_File (Name : String) return Boolean;

   --  Determines if the given string, Name, is the name of an existing file

   --  that is executable. Returns True if so, False otherwise. Note that this

   --  function simply interrogates the file attributes (e.g. using the C

   --  function stat), so it does not indicate a situation in which a file may

   --  not actually be readable due to some other process having exclusive

   --  access.

   function Is_Writable_File (Name : String) return Boolean;

   --  Determines if the given string, Name, is the name of an existing file

   --  that is writable. Returns True if so, False otherwise. Note that this

   --  function simply interrogates the file attributes (e.g. using the C

   --  function stat), so it does not indicate a situation in which a file may

   --  not actually be writeable due to some other process having exclusive

   --  access.

   function Is_Symbolic_Link (Name : String) return Boolean;

   --  Determines if the given string, Name, is the path of a symbolic link on

   --  systems that support it. Returns True if so, False if the path is not a

   --  symbolic link or if the system does not support symbolic links.

   --

   --  A symbolic link is an indirect pointer to a file; its directory entry

   --  contains the name of the file to which it is linked. Symbolic links may

   --  span file systems and may refer to directories.

   procedure Set_Writable (Name : String);

   --  Change permissions on the named file to make it writable for its owner

   procedure Set_Non_Writable (Name : String);

   --  Change permissions on the named file to make it non-writable for its

   --  owner. The readable and executable permissions are not modified.

   procedure Set_Read_Only (Name : String) renames Set_Non_Writable;

   --  This renaming is provided for backwards compatibility with previous

   --  versions. The use of Set_Non_Writable is preferred (clearer name).

   procedure Set_Executable (Name : String);

   --  Change permissions on the named file to make it executable for its owner

   procedure Set_Readable (Name : String);

   --  Change permissions on the named file to make it readable for its

   --  owner.

   procedure Set_Non_Readable (Name : String);

   --  Change permissions on the named file to make it non-readable for

   --  its owner. The writable and executable permissions are not

   --  modified.

   function Locate_Exec_On_Path

     (Exec_Name : String) return String_Access;

   --  Try to locate an executable whose name is given by Exec_Name in the

   --  directories listed in the environment Path. If the Exec_Name does not

   --  have the executable suffix, it will be appended before the search.

   --  Otherwise works like Locate_Regular_File below. If the executable is

   --  not found, null is returned.

   --

   --  Note that this function allocates memory for the returned value. This

   --  memory needs to be deallocated after use.

   function Locate_Regular_File

     (File_Name : String;

      Path      : String) return String_Access;

   --  Try to locate a regular file whose name is given by File_Name in the

   --  directories listed in Path. If a file is found, its full pathname is

   --  returned; otherwise, a null pointer is returned. If the File_Name given

   --  is an absolute pathname, then Locate_Regular_File just checks that the

   --  file exists and is a regular file. Otherwise, if the File_Name given

   --  includes directory information, Locate_Regular_File first checks if the

   --  file exists relative to the current directory. If it does not, or if

   --  the File_Name given is a simple file name, the Path argument is parsed

   --  according to OS conventions, and for each directory in the Path a check

   --  is made if File_Name is a relative pathname of a regular file from that

   --  directory.

   --

   --  Note that this function allocates some memory for the returned value.

   --  This memory needs to be deallocated after use.

   function Get_Debuggable_Suffix return String_Access;

   --  Return the debuggable suffix convention. Usually this is the same as

   --  the convention for Get_Executable_Suffix. The result is allocated on

   --  the heap and should be freed after use to avoid storage leaks.

   function Get_Target_Debuggable_Suffix return String_Access;

   --  Return the target debuggable suffix convention. Usually this is the same

   --  as the convention for Get_Executable_Suffix. The result is allocated on

   --  the heap and should be freed after use to avoid storage leaks.

   function Get_Executable_Suffix return String_Access;

   --  Return the executable suffix convention. The result is allocated on the

   --  heap and should be freed after use to avoid storage leaks.

   function Get_Object_Suffix return String_Access;

   --  Return the object suffix convention. The result is allocated on the heap

   --  and should be freed after use to avoid storage leaks.

   function Get_Target_Executable_Suffix return String_Access;

   --  Return the target executable suffix convention. The result is allocated

   --  on the heap and should be freed after use to avoid storage leaks.

   function Get_Target_Object_Suffix return String_Access;

   --  Return the target object suffix convention. The result is allocated on

   --  the heap and should be freed after use to avoid storage leaks.

   --  The following section contains low-level routines using addresses to

   --  pass file name and executable name. In each routine the name must be

   --  Nul-Terminated. For complete documentation refer to the equivalent

   --  routine (using String in place of C_File_Name) defined above.

   subtype C_File_Name is System.Address;

   --  This subtype is used to document that a parameter is the address of a

   --  null-terminated string containing the name of a file.

   --  All the following functions need comments ???

   function Open_Read

     (Name  : C_File_Name;

      Fmode : Mode) return File_Descriptor;

   function Open_Read_Write

     (Name  : C_File_Name;

      Fmode : Mode) return File_Descriptor;

   function Create_File

     (Name  : C_File_Name;

      Fmode : Mode) return File_Descriptor;

   function Create_New_File

     (Name  : C_File_Name;

      Fmode : Mode) return File_Descriptor;

   procedure Delete_File (Name : C_File_Name; Success : out Boolean);

   procedure Rename_File

     (Old_Name : C_File_Name;

      New_Name : C_File_Name;

      Success  : out Boolean);

   procedure Copy_File

     (Name     : C_File_Name;

      Pathname : C_File_Name;

      Success  : out Boolean;

      Mode     : Copy_Mode := Copy;

      Preserve : Attribute := Time_Stamps);

   procedure Copy_Time_Stamps

     (Source, Dest : C_File_Name;

      Success      : out Boolean);

   function File_Time_Stamp (Name : C_File_Name) return OS_Time;

   --  Returns Invalid_Time is Name doesn't correspond to an existing file

   function Is_Regular_File (Name : C_File_Name) return Boolean;

   function Is_Directory (Name : C_File_Name) return Boolean;

   function Is_Readable_File (Name : C_File_Name) return Boolean;

   function Is_Executable_File (Name : C_File_Name) return Boolean;

   function Is_Writable_File (Name : C_File_Name) return Boolean;

   function Is_Symbolic_Link (Name : C_File_Name) return Boolean;

   function Locate_Regular_File

     (File_Name : C_File_Name;

      Path      : C_File_Name) return String_Access;

   ------------------

   -- Subprocesses --

   ------------------

   subtype Argument_List is String_List;

   --  Type used for argument list in call to Spawn. The lower bound of the

   --  array should be 1, and the length of the array indicates the number of

   --  arguments.

   subtype Argument_List_Access is String_List_Access;

   --  Type used to return Argument_List without dragging in secondary stack.

   --  Note that there is a Free procedure declared for this subtype which

   --  frees the array and all referenced strings.

   procedure Normalize_Arguments (Args : in out Argument_List);

   --  Normalize all arguments in the list. This ensure that the argument list

   --  is compatible with the running OS and will works fine with Spawn and

   --  Non_Blocking_Spawn for example. If Normalize_Arguments is called twice

   --  on the same list it will do nothing the second time. Note that Spawn

   --  and Non_Blocking_Spawn call Normalize_Arguments automatically, but

   --  since there is a guarantee that a second call does nothing, this

   --  internal call will have no effect if Normalize_Arguments is called

   --  before calling Spawn. The call to Normalize_Arguments assumes that the

   --  individual referenced arguments in Argument_List are on the heap, and

   --  may free them and reallocate if they are modified.

   procedure Spawn

     (Program_Name : String;

      Args         : Argument_List;

      Success      : out Boolean);

   --  This procedure spawns a program with a given list of arguments. The

   --  first parameter of is the name of the executable. The second parameter

   --  contains the arguments to be passed to this program. Success is False

   --  if the named program could not be spawned or its execution completed

   --  unsuccessfully. Note that the caller will be blocked until the

   --  execution of the spawned program is complete. For maximum portability,

   --  use a full path name for the Program_Name argument. On some systems

   --  (notably Unix systems) a simple file name may also work (if the

   --  executable can be located in the path).

   --

   --  Spawning processes from tasking programs is not recommended. See

   --  "NOTE: Spawn in tasking programs" below.

   --

   --  Note: Arguments in Args that contain spaces and/or quotes such as

   --  "--GCC=gcc -v" or "--GCC=""gcc -v""" are not portable across all

   --  operating systems, and would not have the desired effect if they were

   --  passed directly to the operating system. To avoid this problem, Spawn

   --  makes an internal call to Normalize_Arguments, which ensures that such

   --  arguments are modified in a manner that ensures that the desired effect

   --  is obtained on all operating systems. The caller may call

   --  Normalize_Arguments explicitly before the call (e.g. to print out the

   --  exact form of arguments passed to the operating system). In this case

   --  the guarantee a second call to Normalize_Arguments has no effect

   --  ensures that the internal call will not affect the result. Note that

   --  the implicit call to Normalize_Arguments may free and reallocate some

   --  of the individual arguments.

   --

   --  This function will always set Success to False under VxWorks and other

   --  similar operating systems which have no notion of the concept of

   --  dynamically executable file. Otherwise Success is set True if the exit

   --  status of the spawned process is zero.

   function Spawn

     (Program_Name : String;

      Args         : Argument_List) return Integer;

   --  Similar to the above procedure, but returns the actual status returned

   --  by the operating system, or -1 under VxWorks and any other similar

   --  operating systems which have no notion of separately spawnable programs.

   --

   --  Spawning processes from tasking programs is not recommended. See

   --  "NOTE: Spawn in tasking programs" below.

   procedure Spawn

     (Program_Name           : String;

      Args                   : Argument_List;

      Output_File_Descriptor : File_Descriptor;

      Return_Code            : out Integer;

      Err_To_Out             : Boolean := True);

   --  Similar to the procedure above, but redirects the output to the file

   --  designated by Output_File_Descriptor. If Err_To_Out is True, then the

   --  Standard Error output is also redirected.

   --  Return_Code is set to the status code returned by the operating system

   --

   --  Spawning processes from tasking programs is not recommended. See

   --  "NOTE: Spawn in tasking programs" below.

   procedure Spawn

     (Program_Name : String;

      Args         : Argument_List;

      Output_File  : String;

      Success      : out Boolean;

      Return_Code  : out Integer;

      Err_To_Out   : Boolean := True);

   --  Similar to the procedure above, but saves the output of the command to

   --  a file with the name Output_File.

   --

   --  Success is set to True if the command is executed and its output

   --  successfully written to the file. If Success is True, then Return_Code

   --  will be set to the status code returned by the operating system.

   --  Otherwise, Return_Code is undefined.

   --

   --  Spawning processes from tasking programs is not recommended. See

   --  "NOTE: Spawn in tasking programs" below.

   type Process_Id is private;

   --  A private type used to identify a process activated by the following

   --  non-blocking calls. The only meaningful operation on this type is a

   --  comparison for equality.

   Invalid_Pid : constant Process_Id;

   --  A special value used to indicate errors, as described below

   function Pid_To_Integer (Pid : Process_Id) return Integer;

   --  Convert a process id to an Integer. Useful for writing hash functions

   --  for type Process_Id or to compare two Process_Id (e.g. for sorting).

   function Non_Blocking_Spawn

     (Program_Name : String;

      Args         : Argument_List) return Process_Id;

   --  This is a non blocking call. The Process_Id of the spawned process is

   --  returned. Parameters are to be used as in Spawn. If Invalid_Pid is

   --  returned the program could not be spawned.

   --

   --  Spawning processes from tasking programs is not recommended. See

   --  "NOTE: Spawn in tasking programs" below.

   --

   --  This function will always return Invalid_Pid under VxWorks, since there

   --  is no notion of executables under this OS.

   function Non_Blocking_Spawn

     (Program_Name           : String;

      Args                   : Argument_List;

      Output_File_Descriptor : File_Descriptor;

      Err_To_Out             : Boolean := True) return Process_Id;

   --  Similar to the procedure above, but redirects the output to the file

   --  designated by Output_File_Descriptor. If Err_To_Out is True, then the

   --  Standard Error output is also redirected. Invalid_Pid is returned

   --  if the program could not be spawned successfully.

   --

   --  Spawning processes from tasking programs is not recommended. See

   --  "NOTE: Spawn in tasking programs" below.

   --

   --  This function will always return Invalid_Pid under VxWorks, since there

   --  is no notion of executables under this OS.

   function Non_Blocking_Spawn

     (Program_Name : String;

      Args         : Argument_List;

      Output_File  : String;

      Err_To_Out   : Boolean := True) return Process_Id;

   --  Similar to the procedure above, but saves the output of the command to

   --  a file with the name Output_File.

   --