I have a static library, liborc-0.4.a with no shared library. I have another library, libschroedinger-1.0.a (no shared) that depends on symbols in liborc-0.4.a. If I run nm on liborc-0.4.a, symbols such as orc_init show up as T (meaning they are defined). I built libschroedinger-1.0.a with the command line flag -lorc-0.4 so it saw the symbols and was ok.
However, now I have a small executable that depends on libschroedinger-1.0.a. It compiles fine, but when I run the linker
gcc -lschroedinger-1.0 -lorc-0.4 -o output input.o
It gives errors such as:
/usr/local/lib/libschroedinger-1.0.a(libschroedinger_1.0_la-schro.o):schro.c:(.text+0x21):
undefined reference to `orc_init'
gcc is sensitive to the order of libraries. When it's compiling liborc-0.4.a in, there is no need for orc_init, so it's not included. The solution is to put the LDFLAGS at the end of the command:
gcc -o output input.o -lschroedinger-1.0 -lorc-0.4
You most probably compiled libschroedinger with shared liborc. Static library is the same as bunch of object files in an archive, so they don't need to see more than headers. Write like the following to be sure (the same apples to liborc).
gcc /path/to/libschroedinger-1.0.a /path/to/liborc-0.4.a -o output input.o
来源：https://stackoverflow.com/questions/5010384/static-library-symbols-not-being-found-even-with-l