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

Hello fellow monks,

I have been having a problem converting a program that works on RedHat9 over to a Fedora (5,6,7) system. After the 3rd use of a font, I get a seg-fault. I have a small program that shows this exact problem

#!/usr/bin/perl
use strict;
use warnings;

use Tk;
use Tk::Font;
use Data::Dumper;

printf "The version of Tk is '%s'\n", $Tk::VERSION;
printf "The version of Tk::Font is '%s'\n", $Tk::Font::VERSION;

make_gui();
MainLoop();

sub make_gui {
    # Main application window.
    my $mw = new MainWindow;

    # Create the font
    my @fontopts = (-family => 'Times', -size => 12, -weight => 'bold'
+);
    my $font = $mw->fontCreate(@fontopts);
    my $psubfonts = $mw->font('subfonts', $font);
    print Data::Dumper->new([$mw->fontActual($font), $psubfonts],
                [qw()])->Indent(1)->Useqq(1)->Dump;

    my $phello = sub { print "Hello\n" };
    my $fr  = $mw->Frame()->pack();

    print "Creating button 1...\n";
    $fr->Button(-text=>"B1", -command=>$phello,-font=>$font)->pack();
    print "Creating button 2...\n";
    $fr->Button(-text=>"B2", -command=>$phello,-font=>$font)->pack();
    print "Creating button 3...\n";
    $fr->Button(-text=>"B3", -command=>$phello, -font=>$font)->pack();
}

[download]

When I run this, I get a seg fault while trying to create the third button.
Comment out the last $fr->Button command and a 2 button window is created.
If I remove all -font commands it works fine (keep adding more buttons etc).
(WIERDNESS: exiting out will cause a segmentation fault.. REMOVE fonts altogether and this fault also does not happen).

I searched here and on google, and I haven't found anything of help, so any assistance is appreciated.

Thanks!!

ps. code updated as per suggestion from zentara

s&&VALKYRIE &&& print $_^q|!4 =+;' *|

Replies are listed 'Best First'.
Re: Tk fonts crash on Fedora
by Ray Smith (Beadle) on Nov 28, 2007 at 15:39 UTC
    Interesting. Note for another data point, I ran the program unchanged under Microsoft Windows XP an it presented no problems there.
[reply]
Re: Tk fonts crash on Fedora
by Tux (Canon) on Nov 28, 2007 at 16:02 UTC

    No problems here (openSUSE 10.3, Linux 2.6.18.8-0.7 x86_64, perl-5.8.8-64all-dor) either, but I admit I use a more recent pTk:

    /tmp 104 > perl test.pl
The version of Tk is '804.027501'
The version of Tk::Font is '4.004'
$VAR1 = "-family";
$VAR2 = "Nimbus Roman No9 L";
$VAR3 = "-size";
$VAR4 = -15;
$VAR5 = "-weight";
$VAR6 = "bold";
$VAR7 = "-slant";
$VAR8 = "roman";
$VAR9 = "-underline";
$VAR10 = 0;
$VAR11 = "-overstrike";
$VAR12 = 0;
$VAR13 = [
  [
    "Nimbus Roman No9 L",
    "urw",
    "Unknown",
    -1,
    "/usr/share/fonts/URW/n021004l.pfb"
  ],
  [
    "Nimbus Roman No9 L",
    "urw",
    "Unknown",
    -1,
    "/usr/share/fonts/URW/n021003l.pfb"
:
:
  [
    "Misc Fixed",
    "Misc",
    "Unknown",
    -1,
    "/usr/share/fonts/misc/10x20.pcf.gz"
  ]
];
Creating button 1...
Creating button 2...
Creating button 3...

    [download]

    Enjoy, Have FUN! H.Merijn
[reply]
[d/l]
Re: Tk fonts crash on Fedora
by zentara (Cardinal) on Nov 28, 2007 at 16:44 UTC
    One thing I see bad in your code, is that you don't define 'myfont'. 
     my $font = $mw->fontCreate(@fontopts);
# that should be 
my $font = $mw->fontCreate('myfont', @fontopts);
#otherwise you need to use $font in the -font option
$fr->Button(-text=>"B1", -command=>$phello,-font=>$font )->pack(

    [download]
    Try cleaning that up and see what happens.
    I'm not really a human, but I play one on earth. Cogito ergo sum a bum
[reply]
[d/l]
      zentara
      Thanks for pointing that blunder out!
      I've changed it to both "fontCreate('myFont', @fontopts)" and to just using "-font=>$font"
      and unfortunately both still show the seg fault.
      Any other ideas??

      I'm going to update the post with that fix

      s&&VALKYRIE &&& print $_^q|!4 =+;' *|
[reply]
        Any other ideas??

        I googled for "Fedora fonts" and apparently there are others who have problems too. Maybe try changing the font to something else, like Helvetica or Courier, possibly Times has a problem in your Fedora version?

        I'm not really a human, but I play one on earth. Cogito ergo sum a bum
[reply]
Re: Tk fonts crash on Fedora
by shmem (Chancellor) on Nov 29, 2007 at 12:25 UTC
    No problem here on Fedora release 7 (Moonshine). Output: 
    The version of Tk is '804.027001'
The version of Tk::Font is '4.004'
$VAR1 = "-family";
$VAR2 = "Nimbus Roman No9 L";
$VAR3 = "-size";
$VAR4 = -16;
$VAR5 = "-weight";
$VAR6 = "bold";
$VAR7 = "-slant";
$VAR8 = "roman";
$VAR9 = "-underline";
$VAR10 = 0;
$VAR11 = "-overstrike";
$VAR12 = 0;
$VAR13 = [
  [
    "Nimbus Roman No9 L",
    "urw",
    "Unknown"
  ],
  [
    "Nimbus Roman No9 L",
    "urw",
    "Unknown"
  ],
  [
    "Liberation Serif",
    "unknown",
    "Unknown"
  ],
...more arrays...
];
Creating button 1...
Creating button 2...
Creating button 3...

    [download]

    Are you missing a font package? (Hint: urw-fonts ;-)

    --shmem 

    _($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}
[reply]
[d/l]
      shmem
      Really? Does it still work if you add say 6 buttons?
      I looked and I am running same Tk (804.027) and Font (4.004) with fc6 and fc7.
      I wonder why yours is working at all. I have seen it do three but fail at 4 or 5.

      Also if it was a failed font package, wouldn't it seg fault at the first use? no?
      If I run it with just 2 buttons it loads (with what looks to be right font) and runs ok
      (other than the seg fault when exiting..which I also don't understand).

      Thanks for the help!!

      s&&VALKYRIE &&& print $_^q|!4 =+;' *|
[reply]
        Yes, it just runs. 6,7...12 buttons, no problem.

        --shmem 

        _($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}
[reply]
Re: Tk fonts crash on Fedora
by eserte (Deacon) on Nov 29, 2007 at 20:40 UTC
    Any chance to get a backtrace from the core dump? 
    gdb perl core
bt

    [download]
[reply]
[d/l]
      eserte
      I don't know where to look for that core file, there isn't one on the directory in which I ran the script??

      s&&VALKYRIE &&& print $_^q|!4 =+;' *|
[reply]
        Maybe there is a limit which prevents from creating core dump files. Try ulimit -c unlimited or a similar construct (this depends on your shell) to allow unlimited core dump files for the current shell process.
[reply]
[d/l]

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