for an example, checkout this: http://pasky.or.cz/dev/glibc/ifunc.c http://pasky.or.cz/dev/glibc/ifunc.c Two implementations are compiled (one is optimized usi

for an example, checkout this: http://pasky.or.cz/dev/glibc/ifunc.c http://pasky.or.cz/dev/glibc/ifunc.c Two implementations are compiled (one is optimized using instructions only available on certain processors), and the decision of which one to use is made at program startup.