Issue
I tried to build task-2.5.1 on my armv81 chromebook inside a termux session. It didn't work due build dependencies so I installed them then uncompressed and started in a fresh new directory. When I ran make VERBOSE=1 I got an undefined reference to __atomic_fetch_add_4 when linking...
[ 98%] Linking CXX executable lex
cd /data/data/com.termux/files/home/src/task-2.5.1/src && /data/data/com.termux/files/usr/bin/cmake -E cmake_link_script CMakeFiles/lex_executable.dir/link.txt --verbose=1
/data/data/com.termux/files/usr/bin/c++ -Wall -Wsign-compare -Wreturn-type -std=c++11 -stdlib=libc++ -O3 -DNDEBUG -rdynamic CMakeFiles/lex_executable.dir/lex.cpp.o -o lex libtask.a commands/libcommands.a columns/libcolumns.a libtask.a -lgnutls -luuid
/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: libtask.a(Nibbler.cpp.o): in function `Nibbler::Nibbler(Nibbler const&)':
Nibbler.cpp:(.text+0x8c): undefined reference to `__atomic_fetch_add_4'
/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: libtask.a(Nibbler.cpp.o): in function `Nibbler::operator=(Nibbler const&)':
Nibbler.cpp:(.text+0xe0): undefined reference to `__atomic_fetch_add_4'
/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: Nibbler.cpp:(.text+0x104): undefined reference to `__atomic_fetch_add_4'
/data/data/com.termux/files/usr/bin/arm-linux-androideabi-ld: libtask.a(Nibbler.cpp.o): in function `Nibbler::~Nibbler()':
Nibbler.cpp:(.text+0x174): undefined reference to `__atomic_fetch_add_4'
clang-8: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [src/CMakeFiles/lex_executable.dir/build.make:90: src/lex] Error 1
make[2]: Leaving directory '/data/data/com.termux/files/home/src/task-2.5.1'
make[1]: *** [CMakeFiles/Makefile2:175: src/CMakeFiles/lex_executable.dir/all] Error 2
make[1]: Leaving directory '/data/data/com.termux/files/home/src/task-2.5.1'
make: *** [Makefile:152: all] Error 2
I found this discussion about undefined references in arm builds. I tried adding a -latomic to CMakeFiles/task_executable.dir/link.txt but it didn't change the output.
Any ideas how to fix this?
Solution
Many thanks to wbsch in this issue (posted just after this one) for the link to the known fix which was successful on my machine, removing the three lines from CMakeLists.txt.
Answered By - Grant Bowman