> Details, please. How do I do that? readelf -aW /lib/libc.so.6 | grep epoll if the symbols are declared WEAK then you can do this (assuming AJ agrees). #pragma weak epoll_whatever should do the trick. In the resulting binary "readelf -aW mybinary | grep epoll" should should you the weak linkage. At runtime: if (epoll_foobar) { ... it's safe to use }