
{*******************************************************}
{                                                       }
{       Turbo Pascal Version 7.0                        }
{       DOS Interface Unit                              }
{                                                       }
{       Copyright (C) 1988,92 Borland International     }
{                                                       }
{*******************************************************}

unit Dos;

{$D-,I-,S-,O+}

interface

const

{ Flags bit masks }

  FCarry     = $0001;
  FParity    = $0004;
  FAuxiliary = $0010;
  FZero      = $0040;
  FSign      = $0080;
  FOverflow  = $0800;

{ File mode magic numbers }

  fmClosed = $D7B0;
  fmInput  = $D7B1;
  fmOutput = $D7B2;
  fmInOut  = $D7B3;

{ File attribute constants }

  ReadOnly  = $01;
  Hidden    = $02;
  SysFile   = $04;
  VolumeID  = $08;
  Directory = $10;
  Archive   = $20;
  AnyFile   = $3F;

type

{ String types }

  ComStr  = string[127];        { Command line string }
  PathStr = string[79];         { File pathname string }
  DirStr  = string[67];         { Drive and directory string }
  NameStr = string[8];          { File name string }
  ExtStr  = string[4];          { File extension string }

{ Registers record used by Intr and MsDos }

  Registers = record
                case Integer of
                  0: (AX,BX,CX,DX,BP,SI,DI,DS,ES,Flags: Word);
                  1: (AL,AH,BL,BH,CL,CH,DL,DH: Byte);
              end;

{ Typed-file and untyped-file record }

  FileRec = record
              Handle: Word;
              Mode: Word;
              RecSize: Word;
              Private: array[1..26] of Byte;
              UserData: array[1..16] of Byte;
              Name: array[0..79] of Char;
            end;

{ Textfile record }

  TextBuf = array[0..127] of Char;
  TextRec = record
              Handle: Word;
              Mode: Word;
              BufSize: Word;
              Private: Word;
              BufPos: Word;
              BufEnd: Word;
              BufPtr: ^TextBuf;
              OpenFunc: Pointer;
              InOutFunc: Pointer;
              FlushFunc: Pointer;
              CloseFunc: Pointer;
              UserData: array[1..16] of Byte;
              Name: array[0..79] of Char;
              Buffer: TextBuf;
            end;

{ Search record used by FindFirst and FindNext }

  SearchRec = record
                Fill: array[1..21] of Byte;
                Attr: Byte;
                Time: Longint;
                Size: Longint;
                Name: string[12];
              end;

{ Date and time record used by PackTime and UnpackTime }

  DateTime = record
               Year,Month,Day,Hour,Min,Sec: Word;
             end;

var

{ Error status variable }

  DosError: Integer;

{ DosVersion returns the DOS version number. The low byte of    }
{ the result is the major version number, and the high byte is  }
{ the minor version number. For example, DOS 3.20 returns 3 in  }
{ the low byte, and 20 in the high byte.                        }

function DosVersion: Word;

{ Intr executes a specified software interrupt with a specified }
{ Registers package.                                            }

procedure Intr(IntNo: Byte; var Regs: Registers);

{ MsDos invokes the DOS function call handler with a specified  }
{ Registers package.                                            }

procedure MsDos(var Regs: Registers);

{ GetDate returns the current date set in the operating system. }
{ Ranges of the values returned are: Year 1980-2099, Month      }
{ 1-12, Day 1-31 and DayOfWeek 0-6 (0 corresponds to Sunday).   }

procedure GetDate(var Year,Month,Day,DayOfWeek: Word);

{ SetDate sets the current date in the operating system. Valid  }
{ parameter ranges are: Year 1980-2099, Month 1-12 and Day      }
{ 1-31. If the date is not valid, the function call is ignored. }

procedure SetDate(Year,Month,Day: Word);

{ GetTime returns the current time set in the operating system. }
{ Ranges of the values returned are: Hour 0-23, Minute 0-59,    }
{ Second 0-59 and Sec100 (hundredths of seconds) 0-99.          }

procedure GetTime(var Hour,Minute,Second,Sec100: Word);

{ SetTime sets the time in the operating system. Valid          }
{ parameter ranges are: Hour 0-23, Minute 0-59, Second 0-59 and }
{ Sec100 (hundredths of seconds) 0-99. If the time is not       }
{ valid, the function call is ignored.                          }

procedure SetTime(Hour,Minute,Second,Sec100: Word);

{ GetCBreak returns the state of Ctrl-Break checking in DOS.    }
{ When off (False), DOS only checks for Ctrl-Break during I/O   }
{ to console, printer, or communication devices. When on        }
{ (True), checks are made at every system call.                 }

procedure GetCBreak(var Break: Boolean);

{ SetCBreak sets the state of Ctrl-Break checking in DOS.       }

procedure SetCBreak(Break: Boolean);

{ GetVerify returns the state of the verify flag in DOS. When   }
{ off (False), disk writes are not verified. When on (True),    }
{ all disk writes are verified to insure proper writing.        }

procedure GetVerify(var Verify: Boolean);

{ SetVerify sets the state of the verify flag in DOS.           }

procedure SetVerify(Verify: Boolean);

{ DiskFree returns the number of free bytes on the specified    }
{ drive number (0=Default,1=A,2=B,..). DiskFree returns -1 if   }
{ the drive number is invalid.                                  }

function DiskFree(Drive: Byte): Longint;

{ DiskSize returns the size in bytes of the specified drive     }
{ number (0=Default,1=A,2=B,..). DiskSize returns -1 if the     }
{ drive number is invalid.                                      }

function DiskSize(Drive: Byte): Longint;

{ GetFAttr returns the attributes of a file. F must be a file   }
{ variable (typed, untyped or textfile) which has been assigned }
{ a name. The attributes are examined by ANDing with the        }
{ attribute masks defined as constants above. Errors are        }
{ reported in DosError.                                         }

procedure GetFAttr(var F; var Attr: Word);

{ SetFAttr sets the attributes of a file. F must be a file      }
{ variable (typed, untyped or textfile) which has been assigned }
{ a name. The attribute value is formed by adding (or ORing)    }
{ the appropriate attribute masks defined as constants above.   }
{ Errors are reported in DosError.                              }

procedure SetFAttr(var F; Attr: Word);

{ GetFTime returns the date and time a file was last written.   }
{ F must be a file variable (typed, untyped or textfile) which  }
{ has been assigned and opened. The Time parameter may be       }
{ unpacked throgh a call to UnpackTime. Errors are reported in  }
{ DosError.                                                     }

procedure GetFTime(var F; var Time: Longint);

{ SetFTime sets the date and time a file was last written.      }
{ F must be a file variable (typed, untyped or textfile) which  }
{ has been assigned and opened. The Time parameter may be       }
{ created through a call to PackTime. Errors are reported in    }
{ DosError.                                                     }

procedure SetFTime(var F; Time: Longint);

{ FindFirst searches the specified (or current) directory for   }
{ the first entry that matches the specified filename and       }
{ attributes. The result is returned in the specified search    }
{ record. Errors (and no files found) are reported in DosError. }

procedure FindFirst(Path: PathStr; Attr: Word; var F: SearchRec);

{ FindNext returs the next entry that matches the name and      }
{ attributes specified in a previous call to FindFirst. The     }
{ search record must be one passed to FindFirst. Errors (and no }
{ more files) are reported in DosError.                         }

procedure FindNext(var F: SearchRec);

{ UnpackTime converts a 4-byte packed date/time returned by     }
{ FindFirst, FindNext or GetFTime into a DateTime record.       }

procedure UnpackTime(P: Longint; var T: DateTime);

{ PackTime converts a DateTime record into a 4-byte packed      }
{ date/time used by SetFTime.                                   }

procedure PackTime(var T: DateTime; var P: Longint);

{ GetIntVec returns the address stored in the specified         }
{ interrupt vector.                                             }

procedure GetIntVec(IntNo: Byte; var Vector: Pointer);

{ SetIntVec sets the address in the interrupt vector table for  }
{ the specified interrupt.                                      }

procedure SetIntVec(IntNo: Byte; Vector: Pointer);

{ FSearch searches for the file given by Path in the list of    }
{ directories given by DirList. The directory paths in DirList  }
{ must be separated by semicolons. The search always starts     }
{ with the current directory of the current drive. The returned }
{ value is a concatenation of one of the directory paths and    }
{ the file name, or an empty string if the file could not be    }
{ located.                                                      }

function FSearch(Path: PathStr; DirList: String): PathStr;

{ FExpand expands the file name in Path into a fully qualified  }
{ file name. The resulting name consists of a drive letter, a   }
{ colon, a root relative directory path, and a file name.       }
{ Embedded '.' and '..' directory references are removed.       }

function FExpand(Path: PathStr): PathStr;

{ FSplit splits the file name specified by Path into its three  }
{ components. Dir is set to the drive and directory path with   }
{ any leading and trailing backslashes, Name is set to the file }
{ name, and Ext is set to the extension with a preceding dot.   }
{ Each of the component strings may possibly be empty, if Path  }
{ contains no such component.                                   }

procedure FSplit(Path: PathStr; var Dir: DirStr;
  var Name: NameStr; var Ext: ExtStr);

{ EnvCount returns the number of strings contained in the DOS   }
{ environment.                                                  }

function EnvCount: Integer;

{ EnvStr returns a specified environment string. The returned   }
{ string is of the form "VAR=VALUE". The index of the first     }
{ string is one. If Index is less than one or greater than      }
{ EnvCount, EnvStr returns an empty string.                     }

function EnvStr(Index: Integer): String;

{ GetEnv returns the value of a specified environment variable. }
{ The variable name can be in upper or lower case, but it must  }
{ not include the '=' character. If the specified environment   }
{ variable does not exist, GetEnv returns an empty string.      }

function GetEnv(EnvVar: String): String;

{ SwapVectors swaps the contents of the SaveIntXX pointers in   }
{ the System unit with the current contents of the interrupt    }
{ vectors. SwapVectors is typically called just before and just }
{ after a call to Exec. This insures that the Exec'd process    }
{ does not use any interrupt handlers installed by the current  }
{ process, and vice versa.                                      }

procedure SwapVectors;

{ Keep (or Terminate Stay Resident) terminates the program and  }
{ makes it stay in memory. The entire program stays in memory,  }
{ including data segment, stack segment, and heap. The ExitCode }
{ corresponds to the one passed to the Halt standard procedure. }

procedure Keep(ExitCode: Word);

{ Exec executes another program. The program is specified by    }
{ the Path parameter, and the command line is specified by the  }
{ CmdLine parameter. To execute a DOS internal command, run     }
{ COMMAND.COM, e.g. "Exec('\COMMAND.COM','/C DIR *.PAS');".     }
{ Note the /C in front of the command. Errors are reported in   }
{ DosError. When compiling a program that uses Exec, be sure    }
{ to specify a maximum heap size as there will otherwise not be }
{ enough memory.                                                }

procedure Exec(Path: PathStr; ComLine: ComStr);

{ DosExitCode returns the exit code of a sub-process. The low   }
{ byte is the code sent by the terminating process. The high    }
{ byte is zero for normal termination, 1 if terminated by       }
{ Ctrl-C, 2 if terminated due to a device error, or 3 if        }
{ terminated by the Keep procedure (function call 31 hex).      }

function DosExitCode: Word;

