Hi Rajat, > File x.cpp compiles perfactly, but while linking it throws error saying, > x.o(.gnu.linkonce.t._ZN9AI11BE11getInstanceEv+0x9): In function > `A<B>::getInstance()': > A.h:: undefined reference to `A<B>::_instance' > collect2: ld returned 1 exit status > > Any clue ? You have declared A<B>::_instance in A.h. But in which file have you defined A<B>::_instance? HTH, --Eljay