Uninitialized value error

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

Error: Use of uninitialized value in printf at perl_lib/areg_fparse.pm

package reg_spec.pm;
sub new    {
  my $self        = {};
  my $dummy       = shift;
  my $name        = shift;
  my $offset      = shift;
  my $comment     = shift;
  my @fields      = @_;
  my $fref        = \@fields;
  my $fc          = @fields;
  $self->{name}   = $name;
  $self->{field_ptr} = $fref;
  $self->{offset}    = $offset;
  $self->{comment}   = $comment;
  bless  ($self);
  return $self;
}

package areg_fparse.pm;

my $new_reg = reg_spec->new ($cur_reg_name,$cur_reg_offset,$cur_reg_co
+mment,@cur_fields);

printf $OFILE "<Descr Value=\"%s\"> </Descr>\n",$self->{comment};
[download]

I wonder why this error! Using perl after 2yrs!!

Comment on Uninitialized value error Download Code

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Re: Uninitialized value error by moritz (Cardinal) on May 02, 2012 at 06:48 UTC
`package areg_fparse.pm;` gives me a syntax error. Anyway, "Uninitialized value" is a warning, not an error. And it comes with a line number, which tells you where a value is uninitialized. And once you know the line, it should be pretty easy to figure out which value it is that is undef. Perl 6 - the future is here, just unevenly distributed	[reply] [d/l]
Re: Uninitialized value error by davido (Cardinal) on May 02, 2012 at 06:53 UTC
Where are you setting `$cur_reg_comment`? The code you presented never set a value in `$cur_reg_name`, `$cur_reg_offset`, `$cur_reg_comment`, or `@cur_fields`. If that's all the code, their values are `undef` (except for the array which is `()`). You pass undefined values into the constructor, it passes them straight through to its underlying object stash, and then you print one of those `undef` values back out in line 23. Perl is kind enough to issue a warning that you might be doing something wrong. I'm sure there's more code than you're presenting, but it looks reasonably clear that if `$cur_reg_comment` is empty when you call the constructor, `$obj->{comment}` will be empty when you try to print it. Dave	[reply] [d/l] [select]
Re: Uninitialized value error by Jenda (Abbot) on May 02, 2012 at 09:14 UTC
`sub new { my ($class, $name, $offset, $comment, @fields) = @_; my $self = { name => $name, offset => $offset, comment => $comment, field_ptr => \@fields, }; return bless($self, $class); }` [download] Jenda Enoch was right! Enjoy the last years of Rome.	[reply] [d/l]
Re^2: Uninitialized value error by zeni (Beadle) on May 02, 2012 at 11:44 UTC
Hi All.. I fixed this issue. Was actually trying to access it with a different pointer. Thanks!	[reply]
Re^3: Uninitialized value error by bulk88 (Priest) on May 02, 2012 at 17:56 UTC
Perl doesn't have pointers except for pack and "((\$scalar)+0)".	[reply]