🚀 go-pugleaf

Hi Mark,

Mark Williams wrote in <4006da70$2@newsgroups.borland.com>:
> Having used
> 
> fs := TFileStream.Create(fn, fmCreate or fmShareDenyWrite);

This don't make sense.

fmCreate or fmShareDenyWrite = fmCreate

TFileStream.Create differentiate between fmCreate and other flags.
fmCreate -> FileCreate, other -> FileOpen.

FileCreate use CREATE_ALWAYS and don't use any share flags.

> where fn is the name of a file to open and lock the file.  How do I then
> save to the file without freeing the stream and losing the protection?

You need to write a own TFileStream class (untested):

type
  TFileStreamEx = class(THandleStream)
  public
    constructor Create(const FileName: string; DesiredAccess, ShareMode,
      CreationDisposition: DWORD);
    destructor Destroy; override;
  end;

constructor TFileStreamEx.Create(const FileName: string; DesiredAccess,
  ShareMode, CreationDisposition: DWORD);
begin
  FHandle := CreateFile(PChar(FileName), DesiredAccess,
    ShareMode, nil, CreationDisposition, FILE_ATTRIBUTE_NORMAL, 0);
  if FHandle = INVALID_HANDLE_VALUE then
  begin
    FHandle := 0;
    raise EFOpenError.CreateResFmt(@SFOpenError, [FileName]);
  end;
end;

destructor TFileStreamEx.Destroy;
begin
  if FHandle <> 0 then
    FileClose(FHandle);
end;


  fs := TFileStreamEx.Create(fn, GENERIC_READ or GENERIC_WRITE,
    FILE_SHARE_READ, CREATE_ALWAYS);

Bye Peter.
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