GCC   -l  option is to link the library. It can use for static and share link.  Link -l with library name without the lib prefix and the .a or .so extensions.

Static : gcc   -static -ltest xx.c, it will link with libtest.a

share : gcc –ltest xx.c it will link with libtest.so

GCC -E

If there are some MACRO codes are not easy to understand, you can use gcc –E to expand MACRO to C code.

GCC -save-temps

adding parameters -S -save-temps makes it leave all intermediate files - preprocessed, assembly, objects