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ruabmbua / hidapi-rs

Rust bindings for the hidapi C library
MIT License
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Issues with cross-compiling hidapi for arm #38

Closed phl0 closed 5 years ago

phl0 commented 5 years ago

I have an issue with cross-compiling hidapi for arm architectures. Trying to compile my fork of https://github.com/rwth-afu/UniPager I always end up with the error message: 

--- stderr
thread 'main' panicked at 'Unable to find hidapi-libusb: CrossCompilation', src/libcore/result.rs:1009:5
note: Run with `RUST_BACKTRACE=1` for a backtrace.

I installed libudev-dev on my build host (Ubuntu 16.04 x86) but that did not solve the issue. It may be an issue in combination with pkg-config. I did set some environment variables for pkg-config though:

declare -x PKG_ALLOW_CROSS="1"
declare -x PKG_CONFIG_DIR=""
declare -x PKG_CONFIG_LIBDIR=":/usr/lib/arm-linux-gnueabihf/"
declare -x PKG_CONFIG_SYSROOT="/"
declare -x TARGET="arm-unknown-linux-gnueabihf"

Any hints for further debugging this?

ruabmbua commented 5 years ago

Can you give me a branch, where hidapi is included? I might be able to figure out the problem.

ruabmbua commented 5 years ago

You can try building with the linux-static-hidraw feature. I think you might be hitting a problem, where your distro does not have multiple hidapi backends (for the C library).

On my system, and some others. the libraries are called hidapi-libusb and hidapi-hidraw, but on yours (especially the cross compile environment), the libraries might just not exist.

To link to hidapi in shared mode you need to have hidapi-libusb or hidapi-hidraw in your cross compile environment.

phl0 commented 5 years ago

The branch that I try to compile is called hidraw in my own repo. It is just a PR up to now because it doesn't compile.

Using linux-static-hidrawit built ok. I will check the binary and also test the travis builder. Thanks so far for the support.

phl0 commented 5 years ago

Tested the binary successfully on RPis 1B, 2B and 3B. So using linux-static-hidraw solved the problem here. Still don't understand why linux-shared-hidraw doesn't work though ...

lnicola commented 4 years ago

I just got asked about this in a crate I wrote, but I'm not sure how it's supposed to work. linux-static-hidraw links to libudev, so how can I cross-compile?

As expected, I get: /lib/x86_64-linux-gnu/libudev.so: file not recognized: file format not recognized when trying to link a binary.