(.text+0x6b13): undefined reference to function_name

The function TrustManager::initNewTrustValues(Path&, int) should have a prototype in the corresponding header file.

Some times, even if you are having prototype defined in header file, you may see this error due to type mismatch in arguments or return type. If it is the cause of the error then use type cast. (Some version of compiler can handle this without type casting. So you will not get such errors in different version of linux/gcc)