http://www.perlmonks.org?node_id=1013664


in reply to 'Anonymous' copy via file handle fails

Filehandles are iterators. Once you reach the end, you're at the end, subsequent read/readline reads from the end, there is nothing at the end, so you have to use seek to rewind the FA filehandle before you read it again. 

$ echo > 1

$ perl -MFile::Copy -wE " open $O, 1 or die $!; sub F{copy $O, \*STDOU
+T } F;F; seek $O,0,0; F; "
ECHO is on.
ECHO is on.

$ rm 1

$

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Re^2: 'Anonymous' copy via file handle fails
by Monk::Thomas (Friar) on Jan 17, 2013 at 08:51 UTC
    Hmmm. The strange thing is I actually had a 'rewind' in there at some point but removed it again because it didn't have any impact. However if I change the first copy operation to 
      copy $src_file, $tmp1_fh
    or die "$ERRNO\n";
  seek $tmp1_fh,0,0;

    [download]
    then it magically works now. Thanks for the tip! Maybe there is some other bug lurking in the original program, but now that the basic copy works I'm sure to figure it out.
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