[Solved] - Freeing an assigned but not opened file

[zxandris]

Essentially I'm trying to set the hidden attiribute of a file I create/work with.  I think I'm doing that right, but then it locks the file and CloseFile doesn't work because I don't actually have the file open, Set Attribute doesn't want the file open apparently just assigned, so how do I unassign the file and unlock the file.  Any help here would be marvellous, thanks.

Or if anyone has an actual function to do that it'd be great.  I've searched around and no-where does it say how to close just an assigned file.

[TRon]

I have no idea about what you described. Would it not be simpler to use FileSetAttr as that only requires you to provide a filename (and the attributes) ?

[zxandris]

You know what that would be much simplier, thanks.  My searches believe it or not never came up with that as an option lol.  I'll do this thank you

[TRon]

It might be that you already have the file open to perform other action(s) on the file, in which case you would need to close the file first and then change the attributes (which I imagine is not the nicest of program flow) so perhaps another solution could be more practical for your use case.

Unfortunately there is some (code) context missing so without such context you would have to decide that for yourself 

[zxandris]

It might be that you already have the file open to perform other action(s) on the file, in which case you would need to close the file first and then change the attributes (which I imagine is not the nicest of program flow) so perhaps another solution could be more practical for your use case.

Unfortunately there is some (code) context missing so without such context you would have to decide that for yourself 

I'm just hiding an ini file I use for properties while browsing a directory, so I want to set the attirbute after I've written to the file.  I had code at one point but since i had to restart my pc several times to unlock the file I ended up deleting that.  I think the FileSetAttr thing will do the job - thank you

[TRon]

Thank you for the additional context.

In case using tinifile then the file is already closed when you destroy the object/class and besides that you have no direct way of accessing the filehandle so indeed using SetFileAttr would be the most simple and efficient approach (at least to my current knowledge)

[zxandris]

Awesome, thank you so much.  I'm pretty new to the forum but so far loving how helpful you guys are!

[zxandris]

Okay, so a little check with you guys here, I've made this procedure that should - I think - set the hidden attribute if it's not already set

Code: Pascal  [Select][+][-]

1. procedure TFrameImageBrowser.MakeHidden(const fname : String);
2. var
3.    attri : LongInt;
4. begin
5.      if fileExists(fname) then
6.      begin
7.           try
8.               attri := FileGetAttr(fname);
9.               if Attri <> - 1 then
10.               begin
11.                    if (attri and faHidden)<>0 then
12.                    begin
13.                         attri := attri or faHidden;
14.                         FileSetAttr(fname, attri);
15.                    end;
16.               end;
17.           except
18.                 //
19.           end;
20.      end;
21. end;    
22.  

Will that work, I think it should but I wouldn't mind a little check there because I've never worked with files like this before.

[cdbc]

Hi
Hmmm, shouldn't this:

Code: Pascal  [Select][+][-]

1.                  if (attri and faHidden)<>0 then // <-- ?!?
2.                    begin
3.                         attri := attri or faHidden;
4.                         FileSetAttr(fname, attri);
5.                    end;
6.  
7.  

be like this:

Code: Pascal  [Select][+][-]

1.                  if (attri and faHidden) = 0 then // <-- (!)
2.                    begin
3.                         attri := attri or faHidden;
4.                         FileSetAttr(fname, attri);
5.                    end;

I gather you're checking if "faHidden" is already set, and if not, then you "or" it to the attributes...
Regards Benny

[zxandris]

Hi
Hmmm, shouldn't this:

Code: Pascal  [Select][+][-]

1.                  if (attri and faHidden)<>0 then // <-- ?!?
2.                    begin
3.                         attri := attri or faHidden;
4.                         FileSetAttr(fname, attri);
5.                    end;
6.  
7.  

be like this:

Code: Pascal  [Select][+][-]

1.                  if (attri and faHidden) = 0 then // <-- (!)
2.                    begin
3.                         attri := attri or faHidden;
4.                         FileSetAttr(fname, attri);
5.                    end;

I gather you're checking if "faHidden" is already set, and if not, then you "or" it to the attributes...
Regards Benny

You see, this is why I needed someone to check my work lol. 

Thank you so much!

[TRon]

Hmmm, shouldn't this:

Indeed and a good catch cdbc.

Even while/when your correction is evident, and for this kind of situation I prefer

Code: Pascal  [Select][+][-]

1. if (attri and faHidden)<>faHidden
2.  

in order to make it even more evident.

BTW: I haven't encountered it myself but be aware that this way it is theoretical possible to hide volumes.

[zxandris]

Hmmm, shouldn't this:

Indeed and a good catch cdbc.

Even while/when your correction is evident, and for this kind of situation I prefer

Code: Pascal  [Select][+][-]

1. if (attri and faHidden)<>faHidden
2.  

in order to make it even more evident.

BTW: I haven't encountered it myself but be aware that this way it is theoretical possible to hide volumes.

That does make it easier to remember what I'm doing there and is more evident as you say.

Thanks guys,

CJ

[zxandris]

Okay, weird, but that function we've been working on seems to still lock the file becuase the next time I go to write to it I get a file is in use error.  Any ideas, becuase I'm lost

[zxandris]

I experimented and it appears that for the ini i use I have to unhide the file to enable writing to it, so that's what I did. I'm not entirely sure this is right but it appears to work.

Code: Pascal  [Select][+][-]

1. procedure TFrameImageBrowser.MakeUnHidden(const fname : String);
2. var
3.    attri : LongInt;
4. begin
5.      if fileExists(fname) then
6.      begin
7.           try
8.               attri := FileGetAttr(fname);
9.               if Attri <> - 1 then
10.               begin
11.                   if (attri and faHidden) = faHidden then
12.                   begin
13.                        attri := attri xor faHidden;
14.                        FileSetAttr(fname, attri);
15.                   end;
16.               end;
17.           except
18.                 //
19.           end;
20.      end;
21.      sleep(25);
22. end;  
23.  

It's probably a bit clunky, but as I said it appears to work.

[zxandris]

It appears I lied, that doens't work at all, it's just my error grabbing stopped me realising lol.  SHould've run it debug!

Help!  Lol, I have no idea how the file is getting locked, or why even.  Is my unhiding not working, I'm not entirely sure how to set the attribute to remove the faHidden to be honest.