Subj : Directory Listing
To   : Robert Wolfe
From : mark lewis
Date : Thu Nov 27 2014 05:46 pm


On Thu, 27 Nov 2014, Robert Wolfe wrote to All:

 RW> I am trying to get a listing of files in the currently logged
 RW> directory and output those to a text file.

ok, that's simple enough...

 RW> However, I cannot seem to figure out how to do this with the 
 RW> FindFirst() and FindNext() functions in FreePascal.  The example I 
 RW> tried to base my own code on is as follows:

[chomp]

 RW> Unfortunately, I was not able to get my example (which follows) to
 RW> work: 

 RW> Procedure GenDirFile ;
 RW>   Var SR:       TSearchRec ;
 RW>       DirList:  TStrings;
 RW>       Path:     String;
 RW>       DirFile:  Text;
 RW>   Begin ;
 RW>     Assign(DirFile, 'directory.lst') ;
 RW>     Rewrite(DirFile) ;
 RW>     DirList := TStringsList.Create;
 RW>     if FindFirst('*.zip', faArchive, SR) = 0 then
 RW>       begin
 RW>         repeat
 RW>           WriteLn(DirFile, SR.Name);
 RW>         until FindNext(SR) <> 0;
 RW>         FindClose(SR);
 RW>       end;
 RW>      Close(DirFile);
 RW>     End ;

 RW> Is there something I am doing wrong here?

ok, there's several things going on here... i won't step through all of them 
but since you are attempting to use tstrings, let's go a little further and use 
a tstringlist instead... mainly because tstrings is designed to be inherited by 
other objects whch perform specialized tasks... tstringlist is one such 
object...

the second thing is that you're not doing anything with the DirList that you've 
created... you are, however, attempting to write the filenames directly to your 
output file... that's ok but since we're using the tstringlist, all that stuff 
is done for you...

there's a few other things but for now, let's look at this...

1. create our tstringlist object
2. fill our object with the files returned by findfirst/findnext
3. when all files are found, write our stringlist to a file

nice and easy... especially since the stringlist object already does a huge 
amount of heavy lifting for us ;)

so here's the full code (!) of a working program... this was done on a vista 
machine using FPC's trunk code (FPC 2.7.1) from their repository... i also 
tested it on OS/2 eCS with FPC 2.6.4 and on a Linux with FPC 2.6.5 (the fixes 
branch of FPC 2.6)...

===== snip =====
program DirectoryList;

// we need the following unit libraries
uses Sysutils, Classes;
// Sysutils for findfirst and friends
// Classes for TStringList and friends

Procedure GenDirFile;
  Var SR:       TSearchRec;
      DirList:  TStringList;
  Begin;
    // create the class to hold the returned filenames
    DirList := TStringList.Create;
    // let's sort the list
    DirList.Sorted := True;
    if FindFirst('*.*', faArchive, SR) = 0 then
      begin
        repeat
          // add the returned filename to the list
          DirList.Add(SR.Name);
        until FindNext(SR) <> 0;
        // all done, close the find handle
        FindClose(SR);
      end;
    // now let's write our list of filenames to a text file.
    DirList.SaveToFile('directory.lst');
  End ;

begin
  GenDirFile;
end.
===== snip =====

 RW> Any help anyone can give would be greatly appreciated.

how's that? ;)


(!) please try to reduce the problem to the minimal code needed for a working 
program that shows the failure or problem. partial code is ok in some cases but 
that'll come later ;)

)\/(ark

If you think it's expensive to hire a professional to do the job, wait until 
you hire an amateur.

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 * Origin:  (1:3634/12.71)

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