/usr/bin/ld: /home/v6nX3s/prog-659e02.o: in function `main':
prog.cpp:(.text+0xa): undefined reference to `a::my_lambda'
/usr/bin/ld: prog.cpp:(.text+0x16): undefined reference to `a::my_lambda'
/usr/bin/ld: prog.cpp:(.text+0x3c): undefined reference to `a::my_lambda'
/usr/bin/ld: prog.cpp:(.text+0x5a): undefined reference to `a::my_lambda'
/usr/bin/ld: prog.cpp:(.text+0x78): undefined reference to `a::my_lambda'
/usr/bin/ld: /home/v6nX3s/prog-659e02.o:prog.cpp:(.text+0x7e): more undefined references to `a::my_lambda' follow
clang: error: linker command failed with exit code 1 (use -v to see invocation)