Re: AW: AW: Use of uninitialized valued in concatenation....
Frank Maas wrote: On Sat, Aug 23, 2003 at 01:55:03PM +0200, Marcel Greter wrote: This is not a very good solution. You would also catch the case where $_ is 0, which may should not happen. You would better do Yes... I always fall into that pithole. I think this is because I find the 'defined(...) ? ... : ...' phrase is kinda ugly. Silly me, I know. $_ = defined $_ ? $_ : "NULL"; perl 5.9 has introduced a new operator //= to make it spiffy, so you'd write the above as: $_ //= "NULL"; __ Stas BekmanJAm_pH --> Just Another mod_perl Hacker http://stason.org/ mod_perl Guide ---> http://perl.apache.org mailto:[EMAIL PROTECTED] http://use.perl.org http://apacheweek.com http://modperlbook.org http://apache.org http://ticketmaster.com -- Reporting bugs: http://perl.apache.org/bugs/ Mail list info: http://perl.apache.org/maillist/modperl.html
Re: Re: AW: AW: Use of uninitialized valued in concatenation....
On Sat, Aug 23, 2003 at 01:55:03PM +0200, Marcel Greter wrote: > > This is not a very good solution. You would also catch the case where $_ > is 0, which may should not happen. You would better do Yes... I always fall into that pithole. I think this is because I find the 'defined(...) ? ... : ...' phrase is kinda ugly. Silly me, I know. > $_ = defined $_ ? $_ : "NULL"; Still... I don't know if I like toying around with $_. Especially since you change the real array value (and not a copy) and this might cause problems later on (should you use the values somewhere else as well). But why are we talking about this on a mod_perl list. Sorry guys. --Frank -- Reporting bugs: http://perl.apache.org/bugs/ Mail list info: http://perl.apache.org/maillist/modperl.html
Re: Re: AW: AW: Use of uninitialized valued in concatenation....
-CUT--
my $val=$_||'NULL'; print qq($val);
-CUT--
This is not a very good solution. You would also catch the case where $_
is 0, which may should not happen. You would better do
foreach (@table_data) {
$_ = defined $_ ? $_ : "NULL";
print qq($_); # Here is line 42
}
Basically you also simply could use the warnings pragma within this sub :
no warnings "uninitialized";
greets, Marcel
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Re: AW: AW: Use of uninitialized valued in concatenation....
Am Sat, 23 Aug 2003 09:48:05 + schrieb B. Fongo:
> foreach (@table_data)
> {
>
>print qq($_); # Here is line 42
> }
as Frank already pointed out, your trouble is the uninitialized $_ value
you have in line 42 (which is exactly what the warning tells you, BTW).
the reason for this is very probably that @table_data contains items
that have not been initialized (=> they have no value, not even an
empty value assigned to them). @table_data is filled from
database, so _check your database_. I bet you will find "null" values in
here.
if you don't want to output anything if the database delivers such a null
value simply replace your line 42 with
-CUT--
print qq($_) if $_;
-CUT--
if you want to output an empty line for null values, then do as Frank
suggested:
-CUT--
my $val=$_||'NULL'; print qq($val);
-CUT--
and no, this has definitively absolute nothing to do with mod_perl, thats
just expected and normal perl behaviour.
happy hacking
udo
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AW: AW: Use of uninitialized valued in concatenation....
Oh yes I did. I always try my script on the command line to ensure the
syntax are ok before running them on the web server with mod_perl. So
the error has to do with mod_perl. Perhaps you may want to take a look
of some examples:
I have a file (output_tab.pm) that I use to generate tables dynamically.
Even though it serves its purpose, it goes on generating this error:
Script_name.pl: Use of uninitialized value in concatenation (.) or
string at output_tab.pm line 42.
I went through this section of mod_perl docs und thought Ive understood
it, but I cant feature out the error. Ill appreciate any help.
Below is my module and a script that triggers such error.
#
output_tab.pm
#-
# Modulname: output_tab.pm
#-
use strict;
package output_tab;
use vars qw(@ISA @EXPORT);
require Exporter;
@ISA = qw(Exporter);
@EXPORT = qw(output_tab);
use db_Verbindungen;
sub output_tab{
my ($dbh,$abfrage,$columnspan, $sth,@table_head,@table_data);
($abfrage, @table_head) = @_;
$columnspan = @table_head;
print qq();
print qq();
foreach (@table_head){
print qq($_);
}
print qq();
# Erbnisse Anzeigen
$dbh = db_Verbindungen;
$sth = $dbh->prepare($abfrage);
$sth->execute();
print qq();
while(@table_data = $sth->fetchrow_array){
#my $table_data;
foreach (@table_data)
{
print qq($_); # Here is line 42
}
print qq();
}
print qq( );
print qq();
$sth->finish();
$dbh->disconnect();
}
1;
###
#!/usr/bin/perl -w
#
#Script: pakete_auflisten.pl
#=
use strict;
use db_Verbindungen;
use gui;
use output_tab;
my ($dbh,$abfrage,@table_head);
$abfrage = ('SELECT Gruppe, Paketname, Auftragsdatum, Status,
Statusmeldung FROM Gruppen_Software ORDER BY Auftragsdatum DESC');
@table_head = qw(Gruppe Paketname Auftragsdatum Status Statusmeldung);
# Aufruf der Methode top() des gui.pm Moduls.
top('Paketliste');
# At this stage i call the method output_tab with two arguements.
output_tab($abfrage,@table_head);
# Aufruf der Methode footer() des gui.pm Moduls.
footer();
#== ENDE==
Babs
-Ursprüngliche Nachricht-
Von: Sreeji K Das [mailto:[EMAIL PROTECTED]
Gesendet: Samstag, 23. August 2003 11:10
An: B. Fongo; 'Perrin Harkins'; [EMAIL PROTECTED]
Betreff: Re: AW: Use of uninitialized valued in concatenation
Did u check what's in line # 42 ? If u run the same
script with same params as stand-alone, do u see the
warning ?
Sreeji
--- "B. Fongo" <[EMAIL PROTECTED]> wrote: > It is not a
standard perl error message. I went
> through mod_perl doc at
>
http://perl.apache.org/docs/general/perl_reference/perl_reference.html#T
> racing_Warnings_Reports
>
> and understand that, the error message appear if one
> fails to pass a
> value to a subroutine before using. Looking through
> my codes, you may
> have noticed that, I did pass 2 arguments to the
> subroutine.
>
>
>
> -Ursprüngliche Nachricht-
> Von: Perrin Harkins [mailto:[EMAIL PROTECTED]
> Gesendet: Samstag, 23. August 2003 00:10
> An: B. Fongo
> Cc: [EMAIL PROTECTED]
> Betreff: Re: Use of uninitialized valued in
> concatenation
>
> On Fri, 2003-08-22 at 17:23, B. Fongo wrote:
> > I have a file (output_tab.pm) that I use to
> generate tables
> > dynamically. Even though it serves its purpose, it
> goes on generating
> > this error:
> >
> > Script_name.pl: Use of uninitialized value in
> concatenation (.) or
> > string at output_tab.pm line 42.
>
> This is a standard perl error message. It is not
> related to mod_perl.
> You can look in the perldiag man page for a more
> complete explanation.
>
> - Perrin
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