Tie::File doesn't save

nathanvit has asked for the wisdom of the Perl Monks concerning the following question:

Hello, i'm working with Tie:File module.
I open a file and i push a lot of records in it. They are visible if i print all the array but when i untie it, records are not saved... So i open it as READWRITE as cpan explains in Tie/File.pm but it is the same; any ideas?
PS:I have privilege fo writing on the disk and i also tried flush funcition

my @Card=Leggi($filecard);
....
push(@Card,"BEGIN:VCARD");
push(@Card,"FN:$Nuovo->{'FN:'}");
push(@Card,"N:$Nuovo->{'N:'}");
push(@Card,"END:VCARD");
...
Uscita($filecard,\@Card);


sub Leggi{
    my @Card;
    tie @Card, 'Tie::File', $filecard, mode => O_RDWR;
    ....
    return @Card;
}

sub Uscita{
    my $filecard=shift;
    my $Card=shift;
        
    untie @$Card;
    ...
    exit 0;
}
[download]

---
os: Linux Mandrake 9.0

_{edited by ybiC: s/Tie:/Tie::/ for searchability}

Comment on Tie::File doesn't save Download Code

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Re: Tie:File doesn't save by bobn (Chaplain) on Aug 02, 2003 at 19:26 UTC
If the output file doesn't already exist, your code silently fails to tie the file, From `perldoc Tie::File` `# create the file if it does not exist use Fcntl 'O_RDWR', 'O_CREAT'; tie @array, 'Tie::File', $file, mode => O_RDWR \| O_CREA +T;` [download] And had you checked the return value from tie, as in: `tie (@Card, 'Tie::File', $filecard, mode => O_RDWR ) or die $!;` [download] You would have seen: `No such file or directory at tiefile.pl line 26.` [download] which is why we should always check the return code of anything thing that interacts with the system.. Update: There is also a scope issue - having `my @Card` inside the sub Leggi make this program fail sileltnly even if the tie succeeds. My guess is that `return @Card` returns a list which still isn't tied. I think that either puttting the `my @Card` in the outer scope or returning a reference from the sub (and dealing with it in the code that invokes the sub) would fix this, though I've only tested the first of these options, although you also ahve to remove the @Card = in the @Card = Leggi($filecard); - since the tie already references the array, thi swas unneeded and complicates stuff. Anyhow, since you only posted code fragments, it's hard to test this stuff. In the future, it would help to ensure that everything between <code></code> tags compiles. --Bob Niederman, http://bob-n.com	[reply] [d/l] [select]
Re: Tie::File doesn't save by planetscape (Chancellor) on Jul 07, 2011 at 13:55 UTC
They are visible if i print all the array but when i untie it, records are not saved... Also insure you are using the correct `recsep` for your filesystem. On Windows, I needed: `use Fcntl 'O_RDWR'; use Tie::File; my $file = "./filename.ext"; tie (my @lines, 'Tie::File', $file, mode => O_RDWR,` [download] `recsep => "\n"` `) or die "Can't update $file: $! "; shift @lines; (tied @lines)->flush; untie @lines;` [download] for Strawberry Perl (`This is perl, v5.10.0 built for MSWin32-x86-multi-thread`). While on the same system, using Cygwin Perl (`This is perl, v5.10.1 (*) built for i686-cygwin-thread-multi-64int`), this did the trick: `use Fcntl 'O_RDWR'; use Tie::File; my $file = "./filename.ext"; tie (my @lines, 'Tie::File', $file, mode => O_RDWR) or die "Can't upda +te $file: $! "; shift @lines; (tied @lines)->flush; untie @lines;` [download] Both were operating on the same file, which `file` described as: `$ file filename.ext filename.ext: ASCII text` [download] HTH, planetscape	[reply] [d/l] [select]


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