Cross compile for armv7-unknown-linux-gnueabihf

[eliabieri]

I try to cross compile for armv7-unknown-linux-gnueabihf but I get the following linker error:

w" "-Wl,-O1" "-nodefaultlibs"
  = note: /usr/lib/gcc-cross/arm-linux-gnueabihf/9/../../../../arm-linux-gnueabihf/bin/ld: cannot find -lncursesw
          /usr/lib/gcc-cross/arm-linux-gnueabihf/9/../../../../arm-linux-gnueabihf/bin/ld: cannot find -ltinfo
          collect2: error: ld returned 1 exit status

I've installed the libncurses5-dev package.

Steps to reproduce:

1. Install Cross
2. Clone cursive
3. cd cursive/cursive/examples/
4. Create Cross.toml with the following content:

[build]
pre-build = ["apt-get install libncurses5-dev -y"]

5. Run cross build --target armv7-unknown-linux-gnueabihf

[gyscos]

Hi, and thanks for the question!

The ncurses backend is currently not the easiest one to cross-compile.
You'll need the development libraries installed for the target architecture (which is why -lncursesw and -ltinfo don't work in your case, you need these libraries available to the cross compiler), but even after that, as you noticed the ncurses-sys crate currently compiles and runs a tiny binary at build-time to check some type sizes, which is not easy when you compile for a different architecture than you run.

In the short-term I would recommend trying a different backend like crossterm, which should cross-compile more easily.

[eliabieri]

Thank you very much for your detailed answer!
I'm actually not using the ncurses backend, but it still seems to be required during compilation of cursive.
This is the content of my Cargo.toml:

cursive = { version = "0.20", features = ["termion-backend"] }

[gyscos]

You would need to disable the default features which includes ncurses (default-features = false)

[eliabieri]

Oh, that so good to know!
Maybe would be worth to be added to the docs as others maybe also don't understand this.

[gyscos]

The first page includes a link to the wiki where this is mentioned:
https://github.com/gyscos/cursive/wiki/Backends

But I agree, it could be made more visible, possibly in the lib's top-level documentation.

[eliabieri]

Oh I see. Sorry didn't see that one.
Now I can finally cross compile cursive!

[michalfita]

On Ubuntu 23.04, w/o cargo-cross:

sudo dpkg --add-architecture arm64
sudo apt install gcc-aarch64-linux-gnu binutils-aarch64-linux-gnu libncurses-dev:arm64
cat - <<EOF >> .cargo/config
[target.aarch64-unknown-linux-gnu]
linker = "aarch64-linux-gnu-gcc"
EOF
cargo --target aarch64-linux-gnu-gcc

and it builds nicely with crossterm.