{$S-,R-,I-,V-,F-,B-,A-}

  {*********************************************************}
  {*                    CHAIN.PAS 5.00                     *}
  {*        Copyright (c) TurboPower Software 1987.        *}
  {*                 All rights reserved.                  *}
  {*********************************************************}

unit Chain;
  {-Chaining facility for Turbo 4 or 5}

interface

const
  CloseFilesBeforeChaining : Boolean = True;
  {If false: no files are closed before chaining,
       true: all files but StdIn, StdOut, StdErr, StdPrn are closed}

function Chain4(Path, CmdLine : string) : Word;
  {-Chain to file named in Path
    CmdLine must be no longer than 82 characters
    If Chain4 returns, a DOS error code is in the result}

procedure SetMaxHeap(Bytes : LongInt);
  {-Set maximum heap and adjust DOS memory allocation block}

procedure GetMemDos(var P : Pointer; Bytes : LongInt);
  {-Allocate memory from DOS, returning a pointer to the new block
    Shrink Turbo allocation and relocate free list if forced to
    Returns P = nil if unable to allocate space}

function Pointer2String(P : Pointer) : string;
  {-Convert a pointer to a string suitable for passing on command line}

function String2Pointer(S : string) : Pointer;
  {-Convert a string formatted by Pointer2String to a pointer
    Returns nil if S is an invalid string}

  {==========================================================================}

implementation

  {$L CHAIN}
  {$L GETMEM}

  function Chain4(Path, CmdLine : string) : Word;
    external {CHAIN} ;

  procedure SetIntVec(Num : Byte; Vec : Pointer);
    external {CHAIN} ;

  procedure SetMaxHeap(Bytes : LongInt);
    external {GETMEM} ;

  procedure GetMemDos(var P : Pointer; Bytes : LongInt);
    external {GETMEM} ;

  function Pointer2String(P : Pointer) : string;
    external {GETMEM} ;

  function String2Pointer(S : string) : Pointer;
    external {GETMEM} ;

  procedure RestoreVectors;
    {-Restore SYSTEM interrupt vectors}
  begin
    SetIntVec($00, SaveInt00);
    SetIntVec($02, SaveInt02);
    {$IFNDEF Ver40}
    SetIntVec($1B, SaveInt1B);
    {$ENDIF}
    SetIntVec($23, SaveInt23);
    SetIntVec($24, SaveInt24);
    {$IFNDEF Ver40}
    SetIntVec($34, SaveInt34);
    SetIntVec($35, SaveInt35);
    SetIntVec($36, SaveInt36);
    SetIntVec($37, SaveInt37);
    SetIntVec($38, SaveInt38);
    SetIntVec($39, SaveInt39);
    SetIntVec($3A, SaveInt3A);
    SetIntVec($3B, SaveInt3B);
    SetIntVec($3C, SaveInt3C);
    SetIntVec($3D, SaveInt3D);
    SetIntVec($3E, SaveInt3E);
    SetIntVec($3F, SaveInt3F);
    {$ENDIF}
    SetIntVec($75, SaveInt75);
  end;

end.