Optimizing the runtime linker

Updated: May 06, 2022

The runtime linker supports the following features that you can use to optimize the way it resolves and relocates symbols:

The term “lazy” in all of them can cause confusion, so let's compare them briefly before looking at them in detail:

RTLD_LAZY doesn't imply anything about whether dependencies are loaded; it says where a symbol is looked up. It allows the looking up of symbols that are subsequently opened with the RTLD_GLOBAL flag, when looking up a symbol in an RTLD_LAZY-opened object and its resolution scope fails. The term “resolution scope” is intentional since we don't know what it is by just looking at RTLD_LAZY; it differs depending on whether you specify RTLD_WORLD, RTLD_LAZYLOAD, or both.