????6. ???????
?????????C???????????????г????????????????????????????????????????????????????????????????Щ??????????????????Щ????????????????????д??????????????黥????????????????д??????????????黥???????????????????????????????ɡ??????????????
??????黯?????
????????????
???????????
???????????????????????
?????????.a?????????????????????????????????????????С????????е????????????????????????????????????????????????????????????????????????????????????????
?????????.so??.sa?????????????е??????????????????????????????????????????????????????
???????????????????λ?????
????/usr/include???????????μ?include?????
????/usr/local/include???????????μ?include?????
????/usr/lib
????/usr/local/lib
????/lib
????7. ????????
???????????.a??????????????????.o??????????????????????hello.o?????????libhello.a??
????ar rcs libhello.a hello.o
????ar??gun?鵵?????rcs???replace and create?????libhello??????????????μ?libhello.a???????滻??
??????????????????t????libhello.a
????gcc -Wall main.c libhello.a -o main
?????????????????÷????
????gcc -Wall -L. main.c -o main -lhello ??lhello ?? libhello????д??
???????? -L.??????????λ?????????￡?????libhello.a????????????????????????????￡????????????-L.????????????????????????????????????-I.???????????????????
????8. ????????
??????????????????????????libxxx.so???????hello.o????libhello.so?????????
????gcc -shared -fPIC hello.o -o libhello.so
?????????????????????????????ù????
????gcc -Wall main.o -o main -L. -lhello
??????????????t????????????????????????????????????￡???????ù????
???????????????????????????￡??????gcc?????????????????漸???????
????????.so????????????·???￡?????/usr/lib
??????~/.bash_profile????У?????LD_LIBRARY_PATH????
????????/etc/ld.so.conf?????????????ldconfig????ld.so.cache
???????У?shared?????????????????fPIC???????λ???????position independent code????λ????????????????С??????????λ?????????????κ?????????м????
????9. ???????·??
???????????·??????????????????????????-I -l????????????????Щ??????????????gcc???????? ??????????????в???????????????????C_INCLUDE_PATH??????????????LIBRARY_PATH.??????????????????????????????????????????