SUMMARY On the plot() function (and some other like: hist, bar, stem3, etc.) the evaluation hangs. STEPS TO REPRODUCE 1. Open cantor with octave backend 2. Write 'plot(1:1)' 3. Click 'Evaluate Worksheet' OBSERVED RESULT The program is responsible, but nothing is plotted. The green '>>>' prompt is blinking. At the bottom says 'Calculating...'. EXPECTED RESULT The plot result appears. SOFTWARE/OS VERSIONS Linux: Ubuntu 20.10 KDE Frameworks Version: 5.74.0 Qt Version: 5.14.2 Cantor Version: 20.08.2 Octave Version: 5.2.0 Also reproduces under: Linux: Alt Linux Workstation K 9.1 KDE Plasma Version: 5.18.5 KDE Frameworks Version: 5.70.0 Qt Version: 5.12.9 Cantor Version: 20.12.3 Octave Version: 6.2.0 ADDITIONAL INFORMATION Console output after "Evaluate Worksheet": ``` evaluate worksheet login starting ("/usr/bin/octave-cli", "--silent", "--interactive", "--persist", "--eval", "PS1('CANTOR_OCTAVE_BACKEND_PROMPT:\\#> ');", "--eval", "PS2('CANTOR_OCTAVE_BACKEND_SUBPROMPT:\\#> ');", "--eval", "addpath \"/usr/share/cantor/octavebackend\";", "--eval", "suppress_verbose_help_message(1);") wsStatusChange 1 login done evaluating: "if (length(available_graphics_toolkits()) > 0)\n printf(\"%d\", 1);\nelse\n printf(\"%d\", 0);\nendif" wsStatusChange 0 currentExpressionStatusChanged 1 "if (length(available_graphics_toolkits()) > 0)\n printf(\"%d\", 1);\nelse\n printf(\"%d\", 0);\nendif" readOutput start parsing "CANTOR_OCTAVE_BACKEND_PROMPT:1> " readError readOutput start parsing "1CANTOR_OCTAVE_BACKEND_PROMPT:2> " readError parseOutput: "1" setting result to a type 1 result currentExpressionStatusChanged 2 "if (length(available_graphics_toolkits()) > 0)\n printf(\"%d\", 1);\nelse\n printf(\"%d\", 0);\nendif" wsStatusChange 1 QString::arg: Argument missing: set (0, "defaultfigurevisible","off");, evaluating: "set (0, \"defaultfigurevisible\",\"off\");" wsStatusChange 0 currentExpressionStatusChanged 1 "set (0, \"defaultfigurevisible\",\"off\");" evaluating: "plot(1:1)" readOutput start parsing "CANTOR_OCTAVE_BACKEND_PROMPT:3> " readError parseOutput: "" currentExpressionStatusChanged 2 "set (0, \"defaultfigurevisible\",\"off\");" currentExpressionStatusChanged 1 "plot(1:1)" readOutput start parsing "CANTOR_OCTAVE_BACKEND_PROMPT:4> " readError parseOutput: "" ```
Fount this report (https://bugs.kde.org/show_bug.cgi?id=432892), so not only input functions stay looping forever.
Created attachment 136388 [details] Cantor segfault backtrace Also just discovered that a Segmentation fault occurs when you try to close the worksheet tab (ether with save changes or not) while it's in the 'calculation loop'.
Created attachment 136515 [details] plot command run Test reported issue, can't reproduse it
Hi, as you can see, I can't reproduse this issue. Can you please run commands "available_graphics_toolkits()" and "graphics_toolkits()" Cantor and post result here. Also, can you provide a screenshot from Octave settings ("Settings->Configure Cantor->Octave")?
And about https://bugs.kde.org/show_bug.cgi?id=432892 - I don't think, that you issue related to that report. Input function hanging is well known, but the plot commands don't work with text input and use set of not fully supported commands, so I am sure, that your report about some Cantor bug or some problem with installation.
Created attachment 136517 [details] graphics_toolkits
Created attachment 136519 [details] settings screenshot
Well, this is also well known problem, that Octave plotting via ftlk can work incorrect and hang during plotting in some linux distros. At least in Cantor for sure. So I think, you can try to disable "Embedded" option in Octave (but ftlt window can also hang itself) or run 'graphics_toolkit("gnuplot")' command before plot command and check, is that solves your problem with hanging. And if it have solves the problem, then you can just add the graphics toolkit change command in Cantor Octave autorun command, or in Octave startup file itelf. Additional info about ftlk: On my Ubuntu 20.04 ftlk not working correctly like from Ubuntu 16.04. In early versions we just always have switched from ftlk to any other graphics toolki, but Cantor have had some bugreports about this solution and additional research have showed, that on some distros its work smooth, so we stop to change toolkit and leave graphics toolkit manipulations in user's hand.
Thanks, everything works fine with gnuplot toolkit and octave 5.2, but plotting still hangs if I use octave 6.2. I know that Cantor recommends octave 5.2, so I don't expect it to work, but maybe there are some workarounds?
Well, egori, I will test octave 6.2, but it is better, if you create separete bugreport about octave 6.2. I have close this, because you say, that the problem have gone and "everything works fine".