How to make readonly file not readonly????

[vonskie]

How to make readonly file not readonly????
var
 Attr : Word;
   f    : File;   

{etc}

f:= SourceDirectoryAndFileName;
              Assign(f,ParamStr(1));
              GetFAttr(f,Attr);
              if (Attr and readonly)<>0 then setfattr(>Help?<);

[Bart]

Perhaps:

Code: [Select]

  Attr := FileGetAttr(Fn);
  if ((Attr and faReadOnly) = faReadOnly) then
    FileSetAttr(Fn, Attr and (not faReadOnly));

Bart

[Remy Lebeau]

How to make readonly file not readonly????

Code: [Select]

var
  Attr : Word;
  f    : File;   
  ...

  Assign(f, ParamStr(1));
  GetFAttr(f,Attr);
  if (Attr and ReadOnly) <> 0 then
    SetFAttr(f, Attr and (not ReadOnly));


[Bart]

Mine is 1 line shorter 

Bart

[Remy Lebeau]

Mine is 1 line shorter 

Code: [Select]

Assign(f, ParamStr(1)); GetFAttr(f,Attr);
if (Attr and ReadOnly) <> 0 then SetFAttr(f, Attr and (not ReadOnly));

Now mine is 1 line shorter than yours

Code: [Select]

Assign(f, ParamStr(1)); GetFAttr(f,Attr); SetFAttr(f, Attr and (not ReadOnly));

Now 2 lines shorter

[Bart]

Mine does not need the Assign() part.

Bart

[Fungus]

Code: [Select]

Attr := FileGetAttr(Fn);
if ((Attr and faReadOnly) <> 0) then FileSetAttr(Fn, Attr xor faReadOnly);
Mine is faster than Bart's!

[Thaddy]

Code: Pascal  [Select][+][-]

1. Attr := FileGetAttr(Fn);
2. if ((Attr and faReadOnly) <> 0) then FileSetAttr(Fn, Attr xor faReadOnly);

Mine is faster than Bart's!

Oh well, how about solving it in pure boolean expressions?
I see this? Really? Seriously? THINK!
Can I plz read the proper solution?

Giveaway: just one gets rid of the if then....

[Fungus]

@Thaddy (aka. Grumpy): Do you call for this sollution:

Code: [Select]

FileSetAttr(Fn, FileGetAttr(Fn) and (not faReadOnly));

If so, it is a flawed sollution

[shobits1]

The xor solution may give wrong result.

let's assume you have some flag
F1 = %0001
F2 = %0010
F3 = %0100
F4 = %1000

F  = %1011 ( F1 OR F2 OR F4 )
F AND (NOT F3) = %1011
but F XOR F3   = %1111 = F OR F3  <---- WRONG - With this it includes the flag

So Fungus, sorry but your solution with XOr won't exclude/negate the Flag in question. (or did I miss something?!)

EDIT:
It'll only work when the Flag is set, so it should only used after checking (handle with care, please)

[Fungus]

So Fungus, sorry but your solution with XOr won't exclude/negate the Flag in question. (or did I miss something?!)

EDIT:
It'll only work when the Flag is set, so it should only used after checking (handle with care, please)

As you probably figured out, the XOR method above works 100% as intended since the bits presence is tested before it is flipped. In the later "one line" sollution I reverted to Bart's AND NOT sollution because I'm aware of the fact that it would not work with XOR there