function ProtectFile(sFilename : string) : hFile;
var
hf: hFile;
lwHFileSize, lwFilesize: longword;
ofs : TOFStruct;
begin
if FileExists(sFilename) then
begin
hf := OpenFile(pchar(sFilename), ofs, OF_READ or OF_WRITE or OF_SHARE_EXCLUSIVE);
if hf <> 0 then
begin
lwFilesize := GetFileSize(hf, @lwHFileSize);
if LockFile(hf, 0, 0, lwFilesize, lwHFilesize) then
Result := hf else Result := 0;
end
else Result := 0;
end
else Result := 0;
end;