This is a test of how C++17 static inline/static constexpr variables affect code generation in static and dynamic
linkage scenarios.
You can run the test via make, assuming you have nm and a version of clang supporting C++17 installed.
Sample output:
clang++ -std=c++17 -c main.cc -o main.o
clang++ -std=c++17 -c foo.cc -o foo.o
clang++ -std=c++17 main.o foo.o -o main
clang++ -std=c++17 -DBUILD_SHARED -DFOO_IMPL -shared -fPIC foo.cc -o libfoo.so
clang++ -std=c++17 -DBUILD_SHARED -fPIC main.cc -L./ -Wl,-rpath=./ -lfoo -o main_shared
Key: U = undefined symbol, D = symbol defined in "data", T = symbol defined in "text", V = "weak" symbol
Analysis of artifacts (static linking):
foo.o:
0000000000000000 T increment()
0000000000000000 V Foo::static_inline
0000000000000000 D Foo::regular_static
main.o:
U increment()
0000000000000000 V Foo::static_inline
U Foo::regular_static
0000000000000000 T main
U printf
Running 'main':
Foo::static_inline = 3.000000
Foo::static_constexpr = 42.000000
Foo::regular_static = 99.000000
Analysis of artifacts (dynamic linking):
libfoo.so:
0000000000001100 T increment()
0000000000004030 V Foo::static_inline
0000000000004020 D Foo::regular_static
main_shared:
U increment()
0000000000404040 V Foo::static_inline
U Foo::regular_static
0000000000401140 T main
U printf@@GLIBC_2.2.5
Running 'main_shared':
Foo::static_inline = 3.000000
Foo::static_constexpr = 42.000000
Foo::regular_static = 99.000000