Ugly hack:

  my $pos= tell(DATA);
  chomp( my $x= <DATA> );
  warn "Testing($x)";
  {
    my $fh= do { local(*FH); \*FH };
    open $fh, "<&DATA"  or  die "Can't save DATA: $!\n";
    close DATA  or  warn "Can't close DATA: $!\n";
    open DATA, "<&=".fileno($fh)  or  die "Can't restore DATA: $!\n";
    seek DATA, $pos, 0  or  die "Can't reposition DATA: $!\n";
  }
  warn "Testing";
  chomp( $x= <DATA> );
  warn "Testing($x)";
__END__
some data
[download]

Testing(some data) at redata.pl line 4, <DATA> line 1.
Testing at redata.pl line 12.
Testing(some data) at redata.pl line 14, <DATA> line 1.
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Nope. That doesn't work either. I wrapped your code into a sub, so I could call it multiple times and got:

Testing(some data) at D:\test.pl line 5, <DATA> line 1.
Testing at D:\test.pl line 13.
Testing(some data) at D:\test.pl line 5, <DATA> line 1.
Can't save DATA: Bad file descriptor
[download]

Here is test.pl:

sub Tye
{    
  my $pos= tell(DATA);
  chomp( my $x= <DATA> );
  warn "Testing($x)";
  {
    my $fh= do { local(*FH); \*FH };
    open $fh, "<&DATA"  or  die "Can't save DATA: $!\n";
    close DATA  or  warn "Can't close DATA: $!\n";
    open DATA, "<&=".fileno($fh)  or  die "Can't restore DATA: $!\n";
    seek DATA, $pos, 0  or  die "Can't reposition DATA: $!\n";
  }
  warn "Testing";
}

Tye();
Tye();
__END__
some data
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My mistake. I know this doesn't matter since you found a better solution but this bugged me and I found my mistake.

I was thinking that the "=" in "<&=" was required when using a numeric file descriptor. But the "=" requests an fdopen() instead of a dup(), that is, the new file handle ends up sharing the same file descriptor with the old file handle. So when $fh is closed (triggered when it goes out of scope and gets destroyed), the file descriptor that DATA is using also gets closed out from under it.

So just drop the "=" and my code works.

        - tye (but my friends call me "Tye")

This works, and no filehandles in the error messages:

my @Table;
sub LoadTable
{
    local( $/, $. );
    my $position = tell( DATA );
    @Table = map {chomp; hex} split ' ', <DATA>;   
    seek DATA, $position, 0; # Reset the filehandle, rather then closi
+ng it. 
                             # Never close DATA.
}
[download]

Cheers,
Ovid

Update: Oops. I keep forgetting that __DATA__ doesn't behave like a normal filehandle. See tye's answer below.

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0, 0 is not the position of __DATA__, its the begining of the file.

Also, seek still leaves the filehandle attached to error messages, which I don't want.

my @Table;

{
  my @_Table;
  sub LoadTable {
    unless (@_Table) {
      local $/;
      @_Table = map {chomp; hex} split ' ', <DATA>;
      close DATA;
    }
    @Table = @_Table;
  }
}
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But still memoization is a good solution to many problems where you wouldn't have thought it applied at first....

#!/usr/bin/perl
use strict;
use IO::Handle;
pipe(READ,WRITE) or die;
READ->autoflush(1); #just to be safe
WRITE->autoflush(1);
my $data=<DATA>;
print $data;
print WRITE $data;
*DATA=*READ;
my $data2=<DATA>;
print $data2;
__DATA__
TESTDATA
[download]

AgentM Systems nor Nasca Enterprises nor Bone::Easy nor Macperl is responsible for the comments made by AgentM. Remember, you can build any logical system with NOR.

why not use this instead:

# replace exit(0); with:
exit(close(DATA));

# or (at beginning of script)
sub exit_script {
  close(DATA);
  exit(0);
}

# then replace your exit calls with
exit_script;
[download]

cLive ;-)

Actually, no. I'm writing a module, and short of overloading CORE::exit I don't have control over the exit. That's also why I don't want <DATA> to show up in error messages. Why would the user of my module care if I'm reading the module's DATA? They wouldn't.

On a side note, I'm not sure I understand your answer anyway. The problem isn't with exit, its with warn and die. Specifically, if you have an open filehandle then Perl mentions that when formating your error messages. That's one of the many good reasons to close filehandles when you are done with them, and to use IO::File which observes scope. (normal filehandles are global - although later versions of Perl allow you to scope them via my) My problem is that DATA is not a normal filehandle (as Ovid remembered above). I can't close it, because you can't open it. But once I've read from it, it shows up in error messages. So the question is, how do you keep it open for re-reading, without it showing up in error messages.

Am I missing something here?

Is there any reason why you can't read in the data when the module is loaded, and assign it when you need to?!? ie:

package mod_name;

{
  local $/;
  @mod_name::TableTemplate = map {chomp; hex} split ' ', <DATA>;
  close DATA;
}

my @Table = @mod_name::Table_Template;
[download]

Or am I missing something completely obvious ?!?

cLive ;-)