Doesn't work on systems with ncurses 6

[mortie]

I'm using arch linux, which uses version 6 of ncurses, and thus has no /usr/lib/libncursesw.so.5. Running anything using this library then results in:

Cannot locate native library 'libncursesw.so.5': libncursesw.so.5: cannot open shared object file: No such file or directory

Symlinking /usr/lib/libncursesw.so.6.0 to /usr/lib/libncursesw.so.5 hackishly "solves" the issue, but isn't exactly a great solution.

[azawawi]

I see. Did you try using %*ENV<PERL6_NCURSES_LIB> to specify the ncurses library name/location?

[azawawi]

Did it work for you?

[CIAvash]

@azawawi I set %*ENV<PERL6_NCURSES_LIB> to libncursesw.so.6, it didn't work and the same error was printed. Then I removed precomp files and tried again, it worked. And after this it works even if PERL6_NCURSES_LIB is not set.

Does it have something to do with LIB being constant and the precompilation?

[azawawi]

Sorry for the late reply. Unfortunately, a corrupted .precomp folder is sometimes the cause of some of the Perl 6 modules not working correctly when upgraded.

[blippy]

I had the same problem, but was able to obtain a build as follows:

PERL6_NCURSES_LIB=libncursesw.so.6

then rebuild in the usual way.

[azawawi]

@blippy Thanks for your feedback.

[blippy]

I think it is to do with the fact that at perl6-ncurses6/lib/NCurses6.pm6, line 5 reads:

constant LIB = %*ENV<PERL6_NCURSES_LIB> || 'libncursesw.so.5';

I had a chat on perl6-users-help, where Brandon Allbery stated:

ABI version 6 is not compatible with version 5 (in particular, color handling changed). It is not safe to just use whatever ncurses happens to be around.

Given all of the potential conflict between version 5 and version 6 of ncurses, I have done what I think is the best solution: forked your repo as a basis for NCurses6 - aimed at compatability with version 6 of the library.

This should keep everyone happy (?). Anyone on older systems, or just wanting a vanilla install of Perl 6, can install rakudo in the usual way. Anyone wanting to go down the ncurses 6 route can install my module NCurses6: https://github.com/blippy/perl6-ncurses6 . It also enables users to have both versions on their system, and pick and choose whatever they favour the most.

[azawawi]

Great 👍 But why not have both on the same repository?

[blippy]

I was spooked by Brandon's comment. ncurses6 seems to have better colour support.

I wonder what you think the best way forward is. Should you change 'libncursesw.so.5' to 'libncursesw.so.6', or to 'libncursesw.so', stick with the approach as-is whereby the user has to set PERL6_NCURSES_LIB and remove my NCurses6 as a bad idea, or something else?

Am I right in thinking that NCurses is part of the rakudo distribution?

[azawawi]

Thanks for waking me up 👍

Please try 4c7c837. Your feedback is appreciated.

[blippy]

There seems to be a success. Here's what I did (IIRC):

1. unset my PERL6_NCURSES_LIB, and started a new shell to ensure it was unset
2. recompiled and reinstalled rakudo-star 2017.01
3. Uninstalled NCurses
4. Cloned your repo, and checked out the commit you listed above
5. panda install .
6. cd examples
7. perl6 starfield.pl6

I was presented with a nice moving starfield :) So we have a winner!

Many thanks for fixing this for me.

I think the next step should be for me to remove NCurses6 from ecosystem, as it is redundant. Do you agree?

[azawawi]

Great. I am open to PRs (i.e. more tests, more examples, ideas for NCurses::Simple or NCurses::Lite). Please also checkout the new examples I am adding :)

Also please note panda is now deprecated in favor of zef.