Build failed on Raspberry Pi with Raspbian Buster and GCC 8.3

[mgdelta]

Hi eCAL team,

trying to build your system on a Raspberry Pi 3B+ fails. Build stops first time when building the executable ecal_topic. The linker complains about undefined reference to
__atomic_load_8
__atomic_store_8
__atomic_fetch_add_8

It looks like a problem linking to -latomic which is necessary on armhf systems.

I'm using an actual raspbian (Buster) with GCC 8.3
During build there are a lot of warnings due to some changes after GCC 7.4.
Maybe the -latomic thing is a problem of using GCC 8 or cmake is doing something ugly.

Can you confirm my problem or is it an issue on my side/system?

Thanks!!

[Blutkoete]

I'm not associated with the eCAL team in any way, but I wanted to add that this may not be related to Raspberry Pi 3 or armhf per se, as both the old and the current release build fine with gcc 8.3.0 on my Raspberry Pi 3's running ArchLinuxARM. One main difference is probably that I'm building against the ArchLinuxARM's own versions of protobuf, tclap, asio and simpleini, not the bundled ones.

This is not solving your issue, I know, but maybe it helps someone pinpointing the problem.

[Kerstin-Keller]

So it seems that so far we haven't been building for platforms which do require the special -latomic linker flag in order to use the std::atomic objects.

I suspect the appropriate target_link_libraries command is missing for the eCAL core library
https://github.com/continental/ecal/blob/04a1093bfbb6659763320d9791a40c5c180a3135/ecal/core/src/CMakeLists.txt#L378-L397
and maybe some of the samples.

However, it is not quite clear to me, under which compilation conditions (compiler, platform, e.g. ) the extra linker arguments are necessary.

Amongst others I found this example and this example from llvm where they are trying to detect if the linker argument is necessary.

I am just a bit astonished, as this is / should be(?) part of the standard library, that this is not somehow handled by CMake and the generic flags it sets for one platform (e.g. when enabling the C++11 standard).

[rex-schilasky]

@mgdelta did you succeed with the build ?

[rex-schilasky]

No more feedback here .. just close it.