CMake Warning: libusb dependency

Hey Wolfgang,

I’m running into the following issue whenever I try to build the crazyflie_ros workspace for the crazyswarm package:

CMake Warning at /opt/ros/kinetic/share/catkin/cmake/catkin_package.cmake:166 (message): catkin_package() DEPENDS on '/usr/lib/x86_64-linux-gnu/libusb-1.0.so but neither '/usr/lib/x86_64-linux-gnu/libusb-1.0.so_INCLUDE_DIRS' nor /usr/lib/x86_64-linux-gnu/libusb-1.0.so_LIBRARIES' is defined.

Call Stack (most recent call first): /opt/ros/kinetic/share/catkin/cmake/catkin_package.cmake:102 (_catkin_package) crazyflie_ros/crazyflie_cpp/CMakeLists.txt:19 (catkin_package)

Running the command dpkg -l libusb* gives me:

Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name           Version      Architecture Description
+++-==============-============-============-=================================
ii  libusb-0.1-4:a 2:0.1.12-28  amd64        userspace USB programming library
ii  libusb-1.0-0:a 2:1.0.20-1   amd64        userspace USB programming library
ii  libusb-1.0-0-d 2:1.0.20-1   amd64        userspace USB programming library
ii  libusb-1.0-doc 2:1.0.20-1   all          documentation for userspace USB p
un  libusb-dev     <none>       <none>       (no description available)
un  libusbmuxd-too <none>       <none>       (no description available)
ii  libusbmuxd4:am 1.0.10-2ubun amd64        USB multiplexor daemon for iPhone

Running locate libusb | grep .so gives me:

/lib/x86_64-linux-gnu/libusb-0.1.so.4
/lib/x86_64-linux-gnu/libusb-0.1.so.4.4.4
/lib/x86_64-linux-gnu/libusb-1.0.so.0
/lib/x86_64-linux-gnu/libusb-1.0.so.0.1.0
/usr/lib/x86_64-linux-gnu/libusbmuxd.so.4
/usr/lib/x86_64-linux-gnu/libusbmuxd.so.4.0.0

I am using a “fresh” installation of ubuntu 16.04 (as an admin) and ROS Kinetic. I’ve been searching online for answers but I am coming up short (I probably don’t know the right questions to ask).

Do you have any ideas?

Thanks, Kyle

[whoenig]

Your understanding is correct. Actually you only need to change ROS.cmake files (the other ones are used if you want to build crazyflie_tools standalone, i.e. without any ROS [which might be useful for debugging/trouble shooting]).

If it works with WSL, please let us know and we can update the documentation accordingly.

[kgslovak]

So after doing some digging around, I think I’ve figured out what is going on. The appearance of this warning is due to a change in the catkin_package.cmake files of catkin from version 0.6.19 (included with indigo) to version 0.7.6 (included with kinetic). When parsing through the list of provided dependencies, this script checks a different set of conditions based on which version is being used:

catkin 0.6.19 (line 160): if(NOT ${${depend_name}_FOUND}) catkin 0.7.6 (line 165): if(NOT DEFINED ${depend_name}_INCLUDE_DIRS AND NOT DEFINED ${depend_name}_LIBRARIES)

The “issue” is that the CMakeLists.txt files of the crazyswarm package use find_library(USB_LIB usb-1.0) which only sets the variable USB_LIB to the full path of the desired library. It does not define USB_LIB_FOUND, USB_LIB_INCLUDE_DIRS, or USB_LIB_LIBRARIES. So Catkin 0.6.19 did not throw a warning (which is probably why this condition was changed), however the Kinetic version does.

A search utilizing something like:

find_package(PkgConfig REQUIRED)
pkg_search_module(USB_LIB REQUIRED usb-1.0)

might be more appropriate to “properly” link the library?

As it is, since ${USB_LIB} assess to the full path of the library’s ‘.so’ file and the CMakeLists.txt files use:

target_link_libraries(crazyflie_cpp
  ${USB_LIB}
)

I don’t think this warning is pointing to any issues linking the usb library. BTW, what does the catkin_make -k command do? I have not been able to find any documentation on that option.