my %uberhash=(1,2,3,4);
sub a {
  my %hash=(1,2,3,4);
}

sub b {
  #can see %uberhash
  #can't see %hash
}
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%hash is not seen anywhere but in sub a because 'my' creates variables local to a block (and a subroutine aka function creates a block. Remedies: You could create the variable with 'our' instead of 'my' making the variable globally accessible, or add something like 'my %hash;' outside of the subroutine.

Another possibility would be to return the hash contents as function result and assign that to a globally accessible variable

I suppose that's because there is actually no data in your hash. Perhaps something went wrong in the dbmopen call and you didn't see it because you're not using strict/warnings? Or you declared the hash using "my" in one function but aren't passing it to the other one as a reference? Without a real code snippet it's hard to tell.

By the way, are you sure you want to use dbmopen? That's basically a legacy function, have a look at BerkeleyDB.pm and tie.

cutudl:

You've got two good possibilities above, and here's a third: Perhaps you're working with different hashes, something like this:

$ cat floog.pl
#!/usr/bin/perl

package Utils;
sub make_hash_table {
    %hash = qw(a,b,c,d);
}

package main;
use Data::Dumper;

Utils::make_hash_table();
print Dumper(\%hash);
print Dumper(\%Utils::hash);
$ perl floog.pl
$VAR1 = {};
$VAR1 = {
          'a,b,c,d' => undef
        };
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Why do you have so many radically different possibilities? Simple--you didn't show a simple program that illustrates the problem, or otherwise give enough detail to adequately describe the problems you're having. So we get to play guessing games if we feel motivated enough to try to help. If you spend a little more effort asking good questions, you can greatly increase the possibility of getting a your questions solved quickly.

...roboticus

When your only tool is a hammer, all problems look like your thumb.

my %hash;
populate_hash(%hash);

sub populate_hash{
  my %h = @_;              # Makes a COPY of the paramter
  %h= (k1=>'v1', k2=>'v2); # Populates the LOCAL %h, not '%hash'
}
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 my %hash = populate_hash( ); # Option 1: Use the Return value

 # Option 2: pass a REFERENCE to '%hash', like this:
 populate_hash(\%hash);
  # This requires "populate_hash" to be aware of, and use the referenc
+e, like this:
sub populate_hash{
  my ($href) = @_;              # Makes a COPY of the reference
  $href= {k1=>'v1', k2=>'v2}; # Notice - using CURLY brackets, not par
+ens. This creates a Hash ref.
}
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