calling sub routine problem?

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

in my script, I called a subroutine problem, and it give me the following message:

== main::display_results() called too early to check prototype at ...line.. ===

what could be the problem?
the script proceed to run the routine and print out the results, but what causes the message?

=====

display_results(@sorted, $num);


sub display_results (@$) {
  my @sorted = @_;
  my $number = $_;
  my $count = 0;

  print("User      Disk Usage           \n");
  print("====      =====================\n");

  foreach (@sorted) {
      printf ("Hello  %10d %s\n", $size{$_}, $_);
      $count++;
         if ($count > $num) {
          exit;
      }
  }   }
[download]

Comment on calling sub routine problem? Download Code

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(tye)Re: calling sub routine problem? by tye (Sage) on Apr 22, 2001 at 11:08 UTC
I strongly suggest you stop using subroutine prototypes. The way you have used them above is completely misleading. You have several things you need to learn about Perl but mostly all you need to learn about Perl's subroutine prototypes at this point is "don't use them". (: Now, to questions you didn't ask... Perl subroutines get passed a list of scalar "values" (I put "values" in quotes for reasons that I'll won't explain because they don't affect the problem you are having right now). So if you have `my @sorted= sort qw(this list isn't sorted yet); my $num= 3; display_results( @sorted, $num );` [download] then the `display_results` subroutine gets passed the following list of values: `("isn't","list","sorted","this","yet",3)` You'll note that there is no special mark between "yet" and 3. So, inside the subroutine, @_ will be set to that list. $_ will be set to whatever it was set to before as $_ isn't used for passing arguments to subroutines. So if you want to pass both some scalars and an array/list to a subroutine, then you need to make the array/list as the last argument: `display_results( $num, @sorted ); sub display_results { my( $num, @sorted )= @_;` [download] I suggest you do some reading in any of the many fine sources of documentation on this stuff. (: - tye (but my friends call me "Tye")	[reply] [d/l] [select]
Re: calling sub routine problem? by Eureka_sg (Monk) on Apr 22, 2001 at 13:15 UTC
In supplement to what has been stated so far, you can check out Tom Christiansen's article: Far More Than Everything You've Ever Wanted to Know about Prototypes in Perl for a comprehensive breakdown on how does prototypes really work and the problems attached with them.	[reply]
Re: calling sub routine problem? by dvergin (Monsignor) on Apr 22, 2001 at 08:50 UTC
It would appear that you are calling the sub in your script before (that is: above the place where) you define it. If you don't want to move the full subroutine declaration to the top of your file, you can just put the sub / prototype declaration near the top and then spell out the whole subroutine later.	[reply]