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Re^2: STDERR Restore after redirect

by tultalk (Monk)
on Apr 26, 2018 at 22:59 UTC ( [id://1213647]=note: print w/replies, xml ) Need Help??


in reply to Re: STDERR Restore after redirect
in thread STDERR Restore after redirect

Appreciate response.

However, problem persists.

The filehandle you're printing on got itself closed sometime before now. Check your control flow. print() on closed filehandle

This makes no sense to me

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Re^3: STDERR Restore after redirect
by tultalk (Monk) on Apr 27, 2018 at 00:13 UTC

    I blocked the call to sendmail and the handles were restored and the print command elsewhere executed.

    # SendMail(%mail) or die $Mail::sendMail::error;

    unblocking and

    #restore the file standard handles *STDOUT = $stdout; *STDERR = $stderr; close($fh); print "stdout 2\n";

    results in: print() on closed filehandle $fh at /home/abcus/public_html/httpsdocs/cgi-bin/lib/perl/manageusers.pm line 1124. stderr 2

    So sendMail call is causing problem

    ugh

      print() on closed filehandle $fh # ~~~

      But in the code, you just call print! So, $fh has been selected. The solution might be to

      select $stdout;
      after restoring stdout.

      ($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord }map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
      sendMail call is causing problem

      Yes, some minimal code to demo the problem. Fix is as choroba said.

      #!/usr/bin/perl use warnings; use strict; SendMemberMail(); print "stdout 2\n"; sub SendMemberMail { open my $fh, '>', '1.log' or die $!; MAIL: { local *STDOUT = $fh; local *STDERR = $fh; print "stdout 1\n"; warn "stderr 1\n"; # equivalent Mail:Sendmail code open S,'>','socket' or die; my $oldfh = select(S); $| = 1; select($oldfh); close S; } close $fh; # select(STDOUT); # uncomment to fix }
      poj

      ahem, poj called it when he said

      # equivalent Mail:Sendmail code open S,'>','socket' or die; my $oldfh = select(S); $| = 1; select($oldfh); close S;
      I saw it too when i looked at the SendMail code, he even used the same global filename and varlable that they did.

      notice he says

      # select(STDOUT); # uncomment to fix
      Did you try that?

      And notice he credits choroba for mentioning the fix first

      select $stdout;
      I am mentioning this AGAIN because i understand how frustrating it can be when "someone" skips the actual fix, and wanders away in all odd directions instead.

      The trouble comes from my($oldfh) = select(S); $| = 1; select($oldfh); at http://cpansearch.perl.org/src/ABELTJE/Test-Smoke-1.72/lib/inc/Mail/Sendmail.pm. Note that at the time of my($oldfh) = select(S); the selected default output (while maybe seeming to be *STDOUT) is infact $fh via *STDOUT, so that reselect at the end points directly to $fh rather than back at STDOUT as you might think at first thought. See restoring *STDOUT = $stdout; doesnt do much good when the default print file is directly set to $fh by the select.

      And just as a lark, seeing this

      unless ( socket S, AF_INET, SOCK_STREAM, (getprotobyname 'tcp')[2] ) { return fail("socket failed ($!)")
      brought back memories of doing things before i knew of use IO::Socket;, Hardly thought of in maybe 15 years, still works tho, well kinda. If you were to use low level sockets, (for some comparability reasons id suspect,) is there another way to unbuffer a file than to select it and set $|?

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