delphi Windows API I/O 读写文件

program Project1;

{$APPTYPE CONSOLE}

uses

  SysUtils, Windows;

var

  f: HFILE;

  fn: string;

  lns: AnsiString;

  fsize, amt, i: cardinal;

  AfterLine1: boolean;

const

  data = AnsiString('hello'#13#10'world');

begin

  fn := ExtractFilePath(ParamStr(0)) + 'fileio.txt';

  f := CreateFile(PChar(fn), GENERIC_WRITE, 0, nil, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);

  try

    WriteFile(f, data, length(data), amt, nil);

  finally

    CloseHandle(f);

  end;

  f := CreateFile(PChar(fn), GENERIC_READ, 0, nil, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);

  try

    fsize := GetFileSize(f, nil);

    SetLength(lns, fsize);

    ReadFile(f, lns[1], fsize, amt, nil);

    for i := 1 to fsize do

      case lns[i] of

        #10: AfterLine1 := true;

      else

        if AfterLine1 then

          Write(lns[i]);

      end;

  finally

    CloseHandle(f);

  end;

end.