C++
It seems that the linker is unable to find the definition of the DigPow::digPow function, resulting in the "undefined reference" error.

"/tmp/main-7834c7.o: In function dotest(int, int, int)': main.cpp:(.text+0xa): undefined reference to DigPow::digPow(int, int)'
/tmp/main-7834c7.o: In function digPow_Tests::Fixed__Tests()': main.cpp:(.text._ZN12digPow_Tests12Fixed__TestsEv[_ZN12digPow_Tests12Fixed__TestsEv]+0x12): undefined reference to DigPow::digPow(int, int)'
main.cpp:(.text._ZN12digPow_Tests12Fixed__TestsEv[_ZN12digPow_Tests12Fixed__TestsEv]+0x72): undefined reference to DigPow::digPow(int, int)' main.cpp:(.text._ZN12digPow_Tests12Fixed__TestsEv[_ZN12digPow_Tests12Fixed__TestsEv]+0xd2): undefined reference to DigPow::digPow(int, int)'
main.cpp:(.text._ZN12digPow_Tests12Fixed__TestsEv[_ZN12digPow_Tests12Fixed__TestsEv]+0x132): undefined reference to `DigPow::digPow(int, int)'
clang: error: linker command failed with exit code 1 (use -v to see invocation)"