[CMake] linking main.cpp to class in the same folder.

[eial at cs.bgu.ac.il]

hello.
I've got a class in a folder that I want to run from a main.cpp file, when I compile it, I get a undefined reference to the class's methods.
do I must create a lib from that single class in order to get the linking working?
the CMakeList.txt looks like this:

ADD_LIBRARY(lib1 STATIC ${lib1}) 
ADD_LIBRARY(lib2 STATIC ${lib2}) 

#link libs
target_link_libraries(lib1 ${extlib1})
target_link_libraries(lib2 ${extlib1} ${extlib2})


#list all source files here
ADD_EXECUTABLE(prog main.cpp)

#need to link to some other libraries
TARGET_LINK_LIBRARIES(prog lib1 lib2)

main.cpp looks like that:
#include "Class1.h"

int main(int argc, const char* argv[]) {
   Class1 cls;
   cls.Do1();
   cls.Do2();
   cls.Do3();
   cls.close();
   return 0;
}