random noise in record?

[VilleK]

A string with predefined length (string[x]) is a "shortstring", the old string-type of Delphi 16-bit and Turbo Pascal, and it is not null-terminated. Instead the first byte is the string length. This means it can contain zero-characters. s:='te'#0'st' is a valid shortstring with length 5 (length stored in s[0]).

As already suggested just do a FillChar(MyRecord, sizeof(TMyRecord), 0) to clear the whole record at once.

[Lowercase]

A string with predefined length (string[x]) is a "shortstring", the old string-type of Delphi 16-bit and Turbo Pascal, and it is not null-terminated. Instead the first byte is the string length. This means it can contain zero-characters. s:='te'#0'st' is a valid shortstring with length 5 (length stored in s[0]).

As already suggested just do a FillChar(MyRecord, sizeof(TMyRecord), 0) to clear the whole record at once.

Are you Sure ?

i made a record like noeska last week using delphi 6, i used an hex editor and i saw a null character just after the last char. will send some screen captures when i'm back home

AFAIK, Windows use "pchar type" natively ?

[VilleK]

Delphi 2007:

type
TMyRecord = packed record
name: string[255];
someint: int64;
end;

procedure TForm2.FormCreate(Sender: TObject);
var
  s : tmyrecord;
begin
fillchar(s,sizeof(tmyrecord),$80); //fill with non-zero for testing
s.name := '12'#0'34';
self.caption := inttostr(length(s.name));  //set breakpoint here
end;

The window caption will display the length of the string as 5. If you set a breakpoint where selected and press ctrl-f7 for evaluate and type "s,m" you will see a hex dump of the "s" variable. You will see that there is no zero after the string.

[JernejL]

i made a record like noeska last week using delphi 6, i used an hex editor and i saw a null character just after the last char. will send some screen captures when i'm back home

So how exactly did you write the record to a file?

[tpascal]

When you checks in delphi help the topic about functions and rutines by category you will note tha there are two sections, string and null terminated string rutines, the "string" rutines use the first character for denote the string lenght; nul terminate string are used as pchar.

[Lowercase]

ok I found why... i used strpcopy function which result as pchar

[pascal] TFileIndex = record
FileName: array[0..119] of char;
FilePos: integer;
FileLength: integer;
end;

//and later i use :


strpcopy(Dir.FileName, ExtractFileName(files.Strings[i]));


[/pascal]