everest% cc main2.c adt1.c adt2.c
main2.c:
adt1.c:
adt2.c:
ld64: ERROR 33: Unresolved data symbol "private1" -- 1st referenced by main2.o.
ld64: ERROR 33: Unresolved data symbol "private2" -- 1st referenced by main2.o.
ld64: INFO 60: Output file removed because of error.
cc ERROR:  /usr/lib64/cmplrs/ld64 returned non-zero status 1
everest%