libusb cmake not configuring correctly

[Kikadass]

I am trying to get the repo through FetchContent and compiling the code.
However, I did not install libusb-1.0-0-dev, and I see in the cmake configuration that this project is supposed to download it itself through ExternalProject found in CMake/external_libusb.cmake (https://github.com/IntelRealSense/librealsense/blob/master/CMake/external_libusb.cmake)

The problem is that libusb/core.c needs config.h, which I believe to be generated through autoconf, but this repo is not using autoconf to generate those files. Therefor, there a compiler issue as found in issue #4469

I fixed it by downloading libusb-1.0-0-dev, however, I still think this is a bug, as the code to download libusb exists inside this CMake project, but is not working.
Therefor, I think the external_libusb.cmake should be fixed.

I appreciate your hard work.

[MartyG-RealSense]

Hi @Kikadass The official instructions for installing the librealsense SDK from source code can be found at the link below.

https://github.com/IntelRealSense/librealsense/blob/master/doc/installation.md

A command for manually installing libusb-1.0-0-dev is included in the list of instructions.

sudo apt-get install libssl-dev libusb-1.0-0-dev libudev-dev pkg-config libgtk-3-dev cmake

[Kikadass]

Thank you for your response.

However, as I mentioned, I know that installing libusb manually will fix it, but in the CMake code there is a mechanism to try to install it if it its missing.

That mechanism is broken, therefor I raised an issue/bug. I would recommend fixing it or removing it completely.

[MartyG-RealSense]

I will pass your suggestion on to the development team.

[MartyG-RealSense]

Case closed after feedback passed on to development team.

[Ryanf55]

This affects the last supported version for L515, at version v2.51.1.