ARM (Raspberry PI) build

[lpezet]

I'm trying to build this project for ARM but I'm having an issue. Please bear with me as I'm very rusty when it comes to C/C++ builds.

During the cmake --build . process I get the following error:

[ 50%] Linking C executable hdr_histogram_test
/usr/bin/ld: ../src/libhdr_histogram_static.a(hdr_histogram.c.o): in function `counts_inc_normalised_atomic':
hdr_histogram.c:(.text+0x204): undefined reference to `__atomic_fetch_add_8'
/usr/bin/ld: hdr_histogram.c:(.text+0x220): undefined reference to `__atomic_fetch_add_8'
/usr/bin/ld: ../src/libhdr_histogram_static.a(hdr_histogram.c.o): in function `update_min_max_atomic':
hdr_histogram.c:(.text+0x2dc): undefined reference to `__atomic_load_8'
/usr/bin/ld: hdr_histogram.c:(.text+0x32c): undefined reference to `__atomic_compare_exchange_8'
/usr/bin/ld: hdr_histogram.c:(.text+0x354): undefined reference to `__atomic_load_8'
/usr/bin/ld: hdr_histogram.c:(.text+0x398): undefined reference to `__atomic_compare_exchange_8'
/usr/bin/ld: ../src/libhdr_histogram_static.a(hdr_writer_reader_phaser.c.o): in function `_hdr_phaser_get_epoch':
hdr_writer_reader_phaser.c:(.text+0x18): undefined reference to `__atomic_load_8'
/usr/bin/ld: ../src/libhdr_histogram_static.a(hdr_writer_reader_phaser.c.o): in function `_hdr_phaser_set_epoch':
hdr_writer_reader_phaser.c:(.text+0x58): undefined reference to `__atomic_store_8'
/usr/bin/ld: ../src/libhdr_histogram_static.a(hdr_writer_reader_phaser.c.o): in function `_hdr_phaser_reset_epoch':
hdr_writer_reader_phaser.c:(.text+0x8c): undefined reference to `__atomic_exchange_8'
/usr/bin/ld: ../src/libhdr_histogram_static.a(hdr_writer_reader_phaser.c.o): in function `hdr_phaser_writer_enter':
hdr_writer_reader_phaser.c:(.text+0x1c0): undefined reference to `__atomic_fetch_add_8'
/usr/bin/ld: ../src/libhdr_histogram_static.a(hdr_writer_reader_phaser.c.o): in function `hdr_phaser_writer_exit':
hdr_writer_reader_phaser.c:(.text+0x238): undefined reference to `__atomic_fetch_add_8'
collect2: error: ld returned 1 exit status
gmake[2]: *** [test/CMakeFiles/hdr_histogram_test.dir/build.make:120: test/hdr_histogram_test] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:1007: test/CMakeFiles/hdr_histogram_test.dir/all] Error 2
gmake: *** [Makefile:182: all] Error 2

Now I went ahead, deleted my "build" folder and re-did it all like so:

LDFLAGS="-latomic" cmake ../HdrHistogram_c/
LDFLAGS="-latomic" cmake --build . -v

Got same error, but this time I can see this (thanks to "-v" argument):

/usr/bin/cc -latomic CMakeFiles/hdr_histogram_test.dir/hdr_histogram_test.c.o CMakeFiles/hdr_histogram_test.dir/minunit.c.o -o hdr_histogram_test  ../src/libhdr_histogram_static.a /usr/lib/arm-linux-gnueabihf/libz.so -lpthread -lm -lrt 

Now that won't work because -latomic is like first argument here.
But this works just fine, with -latomic at the end:

/usr/bin/cc CMakeFiles/hdr_histogram_test.dir/hdr_histogram_test.c.o CMakeFiles/hdr_histogram_test.dir/minunit.c.o -o hdr_histogram_test  ../src/libhdr_histogram_static.a /usr/lib/arm-linux-gnueabihf/libz.so -lpthread -lm -lrt  -latomic

What am I doing wrong? Anyone managed to build this project for ARM (Raspberry PI)?

Thanks!

[lpezet]

I found one way, which is to change the src/CMakeLists.txt file like so:

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 2ff2f31..7fadba3 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -47,7 +47,8 @@ function(hdr_histogram_add_library NAME LIBRARY_TYPE DO_INSTALL)
             Threads::Threads
             $<$<BOOL:${HAVE_LIBM}>:m>
             $<$<BOOL:${HAVE_LIBRT}>:rt>
-            $<$<BOOL:${WIN32}>:ws2_32>)
+            $<$<BOOL:${WIN32}>:ws2_32>
+    	    atomic)
     target_include_directories(${NAME}
         PUBLIC
             $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>

But that's far from ideal.
I was hoping for a simple environment variable or alike, but doesn't look possible with cmake (as per https://stackoverflow.com/questions/22316979/how-to-make-cmake-append-linker-flags-instead-of-prepending-them).

Why, oh why, is C/C++ still stuck in the dark ages...