共享库中静态库中的静态函数

Question

I have an application that uses shared objects ( *.so ) as plugins which are loaded at run time. I also have a static library ( *.a ) which contains a few static functions.If both PluginA and PluginB link to the library, will they get their own copies of the static functions as well?

Answer 1

Yes, both plugins will get their own copies of function/symbols contained in the static .a library. For use in shared libraries or plugins the .a library must be position independent code, which can be achieved with the option -fPIC at compilation and link time.

You must also make sure that PluginA and PluginB are not dlopened() with the option RTLD_GLOBAL as there could be nameclashes between the two copies of the static library contained in PluginA and PluginB. This problem of nameclashes becomes even more pronounced in shared libraries if you were to link PluginA and PluginB dynamically at compile time.