Problem Running Perl Debugger

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

I'm getting a "SetConsoleMode failed" error message when I try to use the Perl debugger. I am running ActivePerl 5.8.9 Build 827 on Windows Vista Home Premium. I get the same error on my XP machine (same Perl setup). Is this a known problem with Perl on Windows?

Versions of modules mentioned in the error message.

C:\>ppm query term-r*
+--------------------+-----------+------------------------------------
+-+------+
| name               | version   | abstract                           
+ | area |
+--------------------+-----------+------------------------------------
+-+------+
| Term-ReadKey       | 2.30      | Change terminal modes and perfor...
+ | perl |
| Term-ReadLine      | 1.03      |                                    
+ | perl |
| Term-ReadLine-Perl | 1.0302-r1 | Readline implementation in Perl    
+ | perl |
| Term-ReadLine-Perl | 1.0303    |                                    
+ | site |
+--------------------+-----------+------------------------------------
+-+------+

C:\>perl -d sample.pl

Loading DB routines from perl5db.pl version 1.31
Editor support available.

Enter h or 'h h' for help, or 'perldoc perldebug' for more help.

main::(sample.pl:9):    my $x = 1;

SetConsoleMode failed, LastError=|6| at C:/Perl/lib/Term/ReadKey.pm li
+ne 265.
 at C:/Perl/site/lib/Term/ReadLine/readline.pm line 1581
        readline::readline('  DB<1> ') called at C:/Perl/site/lib/Term
+/ReadLine/Perl.pm line 11
        Term::ReadLine::Perl::readline('Term::ReadLine::Perl=ARRAY(0x3
+62d3f0)', '  DB<1> ') called at C:/Perl/lib/perl5db.pl line 6422
        DB::readline('  DB<1> ') called at C:/Perl/lib/perl5db.pl line
+ 2235
        DB::DB called at sample.pl line 9
  DB<1> x $x
[download]

"Its not how hard you work, its how much you get done."

Comment on Problem Running Perl Debugger Download Code

Replies are listed 'Best First'.

Re: Problem Running Perl Debugger
by SilasTheMonk (Chaplain) on May 19, 2010 at 23:56 UTC

I don't know what is going on here, but I can spot three things that might shed light on the issue.

You have two versions of Term::Readline::Perl installed. I'm not saying I cannot see reasons why that could be, but you might want to elaborate on how it came about.
About 20% of tests for Term::Readline::Perl failed and there a number of bugs. I would also say "have you read the docs", but there does not seem to be any.
Searching for "SetConsoleMode" through the various modules mentioned threw up this interesting snippet in Term::ReadLine

    # the Windows CONIN$ needs GENERIC_WRITE mode to allow
    # a SetConsoleMode() if we end up using Term::ReadKey
    open FIN, (  $^O eq 'MSWin32' && $console eq 'CONIN$' ) ? "+<$cons
+ole" :
                                                              "<$conso
+le";
    open FOUT,">$consoleOUT";

    #OUT->autoflush(1);        # Conflicts with debugger?
    my $sel = select(FOUT);
    $| = 1;                # for DB::OUT
    select($sel);
    $ret = bless [\*FIN, \*FOUT];
  } else {            # Filehandles supplied
    $FIN = $_[2]; $FOUT = $_[3];
    #OUT->autoflush(1);        # Conflicts with debugger?
    my $sel = select($FOUT);
    $| = 1;                # for DB::OUT
    select($sel);
    $ret = bless [$FIN, $FOUT];
  }
[download]

[reply]
[d/l]

Re^2: Problem Running Perl Debugger

by roho (Bishop) on May 20, 2010 at 05:08 UTC

Entering 'perl -d anyprogram.pl' will reproduce the error.

"Its not how hard you work, its how much you get done."

[reply]

Re: Problem Running Perl Debugger
by Khen1950fx (Canon) on May 19, 2010 at 20:07 UTC

Check your environmental variables. I don't use Windows, but on my system, I use xterm, for example, TERM=xterm. Try setting it to TERM=dumb to get rid of the warning.

[reply]

Re^2: Problem Running Perl Debugger

by Athanasius (Archbishop) on Mar 31, 2015 at 03:09 UTC

Thanks for this.

I run Strawberry Perl portable, and seldom use the debugger, so only today discovered that perl -dE 1 gives me the same warning. Which surprised me, as I start Perl from a shortcut that calls my own batch file before calling portableshell.bat, and in my batch file I have set TERM=dumb.

Turns out that between versions 5.18.2 and 5.20.0 the relevant line in portableshell.bat was changed from set TERM=dumb to set TERM=. (So I hadn’t noticed that the second batch file was overriding this set command in the first batch file. Careless. :-( ) By commenting out this line I am now able to set TERM in my own batch file. Problem solved.

Just thought I’d mention this here in case it helps someone else searching for help on the same problem.

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,