Compile err “undefined reference to `SSL_get0_group_name'” when using as a sub_dir of a cmake project

[Staok]

modify the file MAVSDK-xxx/src/mavsdk/core/CMakeLists.txt:
-P ${CMAKE_SOURCE_DIR}/cmake/generate_embedded_xml.cmake
change to:
-P ${PROJECT_SOURCE_DIR}/../cmake/generate_embedded_xml.cmake

so that this lib be used as a sub_dir of a cmake project:

cmake_minimum_required(VERSION 3.15)
project(mavsdk_lib_pkg_cpp)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

# if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
#   add_compile_options(-Wall -Wextra -Wpedantic)
# endif()

# add_definitions("-Wall -Wextra")

# find dependencies
find_package(ament_cmake REQUIRED)
find_package(rclcpp REQUIRED)

# config "MAVSDK" build options
set(SUPERBUILD ON CACHE BOOL "")
set(BUILD_MAVSDK_SERVER OFF CACHE BOOL "")
set(BUILD_WITH_PROTO_REFLECTION OFF CACHE BOOL "")
set(BUILD_SHARED_LIBS ON CACHE BOOL "")
# set(MAVLINK_DIALECT common CACHE STRING "") keep default
set(BUILD_TESTING OFF CACHE BOOL "")
set(BUILD_WITHOUT_CURL OFF CACHE BOOL "")

# set(CMAKE_BUILD_TYPE Release CACHE STRING "")

add_subdirectory(
    ${CMAKE_CURRENT_SOURCE_DIR}/src/MAVSDK-3.10.2
)

add_executable(test_MAVSDK src/test_MAVSDK.cpp)
target_include_directories(test_MAVSDK PUBLIC
  $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
  $<INSTALL_INTERFACE:include/${PROJECT_NAME}>)
target_compile_features(test_MAVSDK PUBLIC c_std_99 cxx_std_17)  # Require C99 and C++17
target_link_libraries(
  test_MAVSDK
  ${rclcpp_TARGETS}
  mavsdk
)
...

and get err:

kanbai@StaokDesktop:~/rover_app_ros2_ws$ colcon build --packages-select mavsdk_lib_pkg_cpp --event-handlers console_direct+
Starting >>> mavsdk_lib_pkg_cpp
[  0%] Built target generate_core_mavlink_xml_header   
[ 57%] Built target mavsdk                                
[ 58%] Built target test_MAVSDK
[ 58%] Linking CXX executable system_tests_runner          
/usr/bin/ld: ../mavsdk/libmavsdk.so.75682307-dirty.75682307-dirty.75682307-dirty: undefined reference to `SSL_get0_group_name'
collect2: error: ld returned 1 exit status                 
gmake[2]: *** [src/MAVSDK-3.10.2/src/system_tests/CMakeFiles/system_tests_runner.dir/build.make:551: src/MAVSDK-3.10.2/src/system_tests/system_tests_runner] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:1111: src/MAVSDK-3.10.2/src/system_tests/CMakeFiles/system_tests_runner.dir/all] Error 2
gmake: *** [Makefile:146: all] Error 2
--- stderr: mavsdk_lib_pkg_cpp
/usr/bin/ld: ../mavsdk/libmavsdk.so.75682307-dirty.75682307-dirty.75682307-dirty: undefined reference to `SSL_get0_group_name'
collect2: error: ld returned 1 exit status
gmake[2]: *** [src/MAVSDK-3.10.2/src/system_tests/CMakeFiles/system_tests_runner.dir/build.make:551: src/MAVSDK-3.10.2/src/system_tests/system_tests_runner] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:1111: src/MAVSDK-3.10.2/src/system_tests/CMakeFiles/system_tests_runner.dir/all] Error 2
gmake: *** [Makefile:146: all] Error 2
---
Failed   <<< mavsdk_lib_pkg_cpp [2.05s, exited with code 2]

Summary: 0 packages finished [2.30s]
  1 package failed: mavsdk_lib_pkg_cpp
  1 package had stderr output: mavsdk_lib_pkg_cpp

os:

kanbai@StaokDesktop:~/rover_app_ros2_ws$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 24.04.3 LTS
Release:        24.04
Codename:       noble

kanbai@StaokDesktop:~/rover_app_ros2_ws$ cat /proc/version
Linux version 6.6.87.2-microsoft-standard-WSL2 (root@439a258ad544) (gcc (GCC) 11.2.0, GNU ld (GNU Binutils) 2.37) #1 SMP PREEMPT_DYNAMIC Thu Jun  5 18:30:46 UTC 2025

cmake version:

kanbai@StaokDesktop:~/rover_app_ros2_ws$ cmake --version
cmake version 3.28.3
CMake suite maintained and supported by Kitware (kitware.com/cmake).

adding this in MAVSDK dir src/CMakeLists.txt: #2489

find_package(OpenSSL REQUIRED)
message(STATUS " === OPENSSL_FOUND: ${OPENSSL_FOUND}")
message(STATUS " === OPENSSL_INCLUDE_DIR: ${OPENSSL_INCLUDE_DIR}")
message(STATUS " === OPENSSL_CRYPTO_LIBRARY: ${OPENSSL_CRYPTO_LIBRARY}")
message(STATUS " === OPENSSL_CRYPTO_LIBRARIES: ${OPENSSL_CRYPTO_LIBRARIES}")
message(STATUS " === OPENSSL_SSL_LIBRARY: ${OPENSSL_SSL_LIBRARY}")
message(STATUS " === OPENSSL_SSL_LIBRARIES: ${OPENSSL_SSL_LIBRARIES}")
message(STATUS " === OPENSSL_LIBRARIES: ${OPENSSL_LIBRARIES}")
message(STATUS " === OPENSSL_VERSION: ${OPENSSL_VERSION}")
message(STATUS " === OPENSSL_APPLINK_SOURCE: ${OPENSSL_APPLINK_SOURCE}")

and get:

--  === OPENSSL_FOUND: TRUE
--  === OPENSSL_INCLUDE_DIR: /usr/include
--  === OPENSSL_CRYPTO_LIBRARY: /usr/lib/x86_64-linux-gnu/libcrypto.so
--  === OPENSSL_CRYPTO_LIBRARIES: /usr/lib/x86_64-linux-gnu/libcrypto.so
--  === OPENSSL_SSL_LIBRARY: /usr/lib/x86_64-linux-gnu/libssl.so
--  === OPENSSL_SSL_LIBRARIES: /usr/lib/x86_64-linux-gnu/libssl.so
--  === OPENSSL_LIBRARIES: /usr/lib/x86_64-linux-gnu/libssl.so;/usr/lib/x86_64-linux-gnu/libcrypto.so
--  === OPENSSL_VERSION: 3.0.13
--  === OPENSSL_APPLINK_SOURCE: 

[julianoes]

Is this with latest MAVSDK? Because we had the issue for a while where it picks up the system openssl libs when it should be using the one from the SUPERBUILD.

This should have been fixed with #2491... I'm puzzled.

[JonasVautherin]

Since you already use lines like:

find_package(ament_cmake REQUIRED)
find_package(rclcpp REQUIRED)

Is there a reason for not doing the same with MAVSDK? I.e. find_package(MAVSDK REQUIRED)?

[Staok]

Since you already use lines like:

find_package(ament_cmake REQUIRED)
find_package(rclcpp REQUIRED)

Is there a reason for not doing the same with MAVSDK? I.e. find_package(MAVSDK REQUIRED)?

Sure, I use the rk3588 orange pi 5 max board (aarch64, ubuntu 24.04) and there is no .deb provided..
So I need to compile it, and for convenience I using the "add_subdirectory()" way to import it to my cmake project(just run compile the proj, no need manually pre-install a bunch of things, that odd for a independent and portable project)

[Staok]

Is this with latest MAVSDK? Because we had the issue for a while where it picks up the system openssl libs when it should be using the one from the SUPERBUILD.

This should have been fixed with #2491... I'm puzzled.

the MAVSDK version is in here:

add_subdirectory(
    ${CMAKE_CURRENT_SOURCE_DIR}/src/MAVSDK-3.10.2
)

its the lastest MAVSDK-3.10.2

[Staok]

I try using the "libmavsdk-dev_3.10.2_debian12_arm64.deb" install on my rk3588 orange pi 5 max board (aarch64, ubuntu 24.04).

[JonasVautherin]

and there is no .deb provided

Note that find_package does not require a .deb. It tries to find a CMake config file. You can just build and install MAVSDK manually.

no need manually pre-install a bunch of things, that odd for a independent and portable project

I don't see how that is odd 🤔.

This said, looking at your log output, it seems that MAVSDK builds correctly but the system_tests_runner fails. I would guess that this happens if mavsdk was built as a static library (.a), because then system_tests_runner will know about curl and openssl.

I see that above you try to set:

set(BUILD_SHARED_LIBS ON CACHE BOOL "")
# set(MAVLINK_DIALECT common CACHE STRING "") keep default
set(BUILD_TESTING OFF CACHE BOOL "")

But at least BUILD_TESTING is not disabled (otherwise it would not try to build the MAVSDK test targets) and therefore I suspect that BUILD_SHARED_LIBS has no effect either. Could you check that?

[Staok]

#2696 (comment)
If Im not install a .deb, and not build and install MAVSDK manually, then there is no way find the MAVSDK lib by find_package..
The build part just not work here.
The odd thing is for me to construct a independent and portable project, shall not manually pre-install a bunch of things to sys public path such as /usr/bin, OK?
The whole cmake config file and os and MAVSDK version all provided, you can just have a try.
This part shall work, because this similar way I used to other many places and they works:

set(BUILD_SHARED_LIBS ON CACHE BOOL "")
set(BUILD_TESTING OFF CACHE BOOL "")

[julianoes]

If Im not install a .deb, and not build and install MAVSDK manually, then there is no way find the MAVSDK lib by find_package..
The build part just not work here.

If you install it manually using cmake --build build --target install for instance, you then have to give cmake the path where it has been installed to, e.g. -DCMAKE_PREFIX_PATH=path/where/installed.

And if you want to install it somewhere specific there is -DCMAKE_INSTALL_PREFIX=path/where/to/install.

[Staok]

If Im not install a .deb, and not build and install MAVSDK manually, then there is no way find the MAVSDK lib by find_package..
The build part just not work here.

If you install it manually using cmake --build build --target install for instance, you then have to give cmake the path where it has been installed to, e.g. -DCMAKE_PREFIX_PATH=path/where/installed.

And if you want to install it somewhere specific there is -DCMAKE_INSTALL_PREFIX=path/where/to/install.

You no need put these basic to me, I am asking other things...

[julianoes]

Alright, sorry. Bottom line, we use and test find_package(MAVSDK). Why don't you use that?

And if not, feel free to create a small reproducible example for us and I'll have a closer look.

[Staok]

I try using the "libmavsdk-dev_3.10.2_debian12_arm64.deb" install on my rk3588 orange pi 5 max board (aarch64, ubuntu 24.04).

This "libmavsdk-dev_3.10.2_debian12_arm64.deb" can be installed in my rk3588 orange pi 5 max board (aarch64, ubuntu 24.04).
So, by this method I can using MAVSDK for now.
But this way to build MAVSDK below is need to be test by using pure gcc env:

add_subdirectory(
    ${CMAKE_CURRENT_SOURCE_DIR}/src/MAVSDK-3.10.2
)

[JonasVautherin]

This part shall work, because this similar way I used to other many places and they works:

If it works, how do you explain that your build fails to build... the tests?

Your problem is happening here:

Linking CXX executable system_tests_runner

You don't need system_tests_runner. Just don't build it and you're good.

[julianoes]

@Staok were you able to resolve your issue, or is there still something to look into?