Fussy, pedantic issue with ncurses libraries

[lars_the_bear]

Hi folks

It seems that the way I installed Gentoo, I ended up with libnursesw.so separated from libtinfow.so. I understand that ncurses can be built this way, or with these libraries combined. So far as I can see, most other Linux distributions have them combined.

My applications that use ncursesw have a single set of Makefiles that work on many Linux platforms -- Fedora, Ubuntu, Raspberry Pi at least -- but they don't work on Gentoo, because they don't explicitly link libtinfow.so, because they don't need to.

The solution is simple, in principle -- just modify all the Makefiles to have '-lncursesw -ltinfow', rather than just '-lnursesw'. But this means that I can no longer maintain a single set of Makefiles for all Linux platforms.

I'm curious whether this split between libncurses and libtinfo is peculiar to the way I set up Gentoo, or whether it will always be like that on a Gentoo system.

And if it will always be like that, I'm wondering if there's some non-ugly way I can modify my makefiles so that the link includes -ltinfow only on Gentoo. Or, perhaps, only on systems where this library exists. I can think of some ugly ways to do this, but surely there is some elegant way?

Incidentally, there seems to have been a fair bit of discussion of this point about ten years ago, and I don't think the Gentoo way of handling libncursesw is accidental. But it does seem to be out of line with other Linux variants.

BR, Lars.

[sam_]

You should use pkg-config instead, not hardcoding libraries: LIBS = $(pkg-config --libs ncursesw).

Anyway, see https://bugs.gentoo.org/457530. There's some more detailed discussion somewhere but I can't dig it up right now.

If you look at the Fedora packaging, they use a linker script hack to try to hide the issue.

Mod edit: Trailing period exorcised from the above URL. — JRG

[lars_the_bear]

[sam_]

The bug is discussion of moving towards the current setup, not away!

You can absolutely get pkg-config files on Raspbian and I'm 95+% sure they work on Cygwin.

(You can also do something like: LIBS = $(shell pkg-config --libs ... || echo -lncursesw ...) anyway.)

[eschwartz]

[lars_the_bear]

@eschwarz

Thank you. But the reason I don't use pkg-config is that I've spent too much time working on minimal and embedded platforms where it isn't present, or doesn't work. I can install gcc and make on Android, for example, but I don't want the hassle of installing all the extra infrastructure that would make pkg-config work. It didn't work properly with Cygwin when I last tried it, nor with the DietPi Raspberry Pi distribution. Admittedly, I haven't used either of these for some time, so the situation might have improved. Still, as a matter of principle, I don't put anything in a Makefile that couldn't be satisfied by Busybox.

In any case, I'm not really looking for a solution, because the solution is a one-line change in a few Makefiles. I appreciate that the use of pkg-config or other build infrastructure would relieve the problem for most users. I was just interested to know whether Gentoo was different in its ncurses provision from the other mainstream Linux distributions I've used, or whether I had just set something up wrongly. I certainly haven't used every Linux distribution that exists, and it's possible that they all differ from one another in this respect.

BR, Lars.

[eschwartz]

[lars_the_bear]

@eschwarz

Thank you; but you've offered a very thorough defence to a criticism I never made

I just wondered if Gentoo was different from what I was familiar with, or whether I'd set it up wrongly. It's different; fine, I'll deal with it.

But thank you for you detailed response, all the same.

BR, Lars.