in reply to J.A.P.H. with intentional eval failure

One option would be to close STDERR; at the top of your program. On my systems the initial eval does not fail because perl (v5.8.1-RC3 built for darwin-thread-multi-2level and v5.6.1 built for i386-linux) interprets %70^72#... as the hash named "70", xored with 72, followed by a comment. Or was the comment about eval failing misdirection on your part?

Replies are listed 'Best First'.
Re^2: J.A.P.H. with intentional eval failure
by ktross (Deacon) on Feb 28, 2005 at 14:23 UTC

    If by 'misdirection' you mean "Gee it sure looks like you posted the wrong code..." then you are right on the money. I've updated it with one that does fail, as advertized, the first time through. It should be noted that this program does not actually eval the string on the first line without modifying it heavily. In the case of the old code something like 'print "J.A.P.H \n";%70^72#...' was being eval-ed. As you mention, that line is runnable.

    Anyways, I've been trying to figure out how to block error messages and STDOUT generated in functions used in my programs that were written by other people. 'close' seems to work great! Thanks! Do you know how to re-open STDERR and STOUT properly?

[reply]
      perldoc -f open has examples. Basically you duplicate STDOUT and STDERR to other filehandles before closing them. Then you duplicate the saved filehandles back to STDOUT and STDERR. 
              print "STDOUT #1\n";warn "STDERR #1\n";
open my $savestdout, '>&', \*STDOUT;
        print "STDOUT #2\n";warn "STDERR #2\n";
open my $savestderr, '>&', \*STDERR;
        print "STDOUT #3\n";warn "STDERR #3\n";
close STDOUT;
        print "STDOUT #4\n";warn "STDERR #4\n";
close STDERR;
        print "STDOUT #5\n";warn "STDERR #5\n";
open STDOUT, '>&', $savestdout;
        print "STDOUT #6\n";warn "STDERR #6\n";
open STDERR, '>&', $savestderr;
        print "STDOUT #7\n";warn "STDERR #7\n";
close $savestdout;
        print "STDOUT #8\n";warn "STDERR #8\n";
close $savestderr;
        print "STDOUT #9\n";warn "STDERR #9\n";

      [download]
      OK, this is bizarre. When I re-open STDOUT, I get output from warn even though STDERR is still closed. perldoc -f warn doesn't describe this behavior.
[reply]
[d/l]
[select]

        Thank you for the guidance. There is lots of good stuff in perldocs. Just shows how much of a noob I am to perl that I didn't go straight to perldoc, instead of searching aimlessly online (darn google!).

        I had to change the code you provided slightly to get it to run on my version of perl. (Adding parenthisis, moving quote locations, nothing major) I'm running perl v5.6.0 built for MSWin32-x86-multi-thread, but don't quote me on that. Anyways, here is the results I get.

        STDOUT #1 STDERR #1 STDOUT #2 STDERR #2 STDOUT #3 STDERR #3 STDERR #4 STDOUT #6 STDERR #6 STDOUT #7 STDERR #7 STDOUT #8 STDERR #8 STDOUT #9 STDERR #9

        Like you said, the line 'STDERR #6' shouldn't be printing....hmmm...

[reply]

In Section Obfuscated Code