Dear all...
I receive this error from the compiler:

sem.obj : error LNK2019: unresolved external symbol "public: __thiscall MissionDefinition::MissionDefinition(double *,double *,int *,int *)" (??0MissionDefinition@@QAE@PAN0PAH1@Z) referenced in function "public: void __thiscall SEM::missionFunctions(void)" (?missionFunctions@SEM@@QAEXXZ)

I have a Qt application the name is sem.h sem.cpp
From sem.cpp I call a function of MissionDefinition Class thanks to the function missionFunctions belonging to SEM....

What do you think the problem is?
Thanks a lot

Guido