RTLDLOCAL

RTLDLOCAL is a flag used with the dynamic loader, ld.so, on Unix-like operating systems. It influences how shared libraries are loaded and linked into an executable program. Specifically, when RTLDLOCAL is used, the dynamic loader will not automatically search for symbols in libraries that are linked to a different object. This means that if a library is loaded with RTLDLOCAL, its symbols will only be visible to the object that directly loaded it. Other objects that might depend on that same library will not be able to resolve symbols from it unless they also explicitly load it.

This behavior contrasts with the default behavior or the behavior of RTLDGLOBAL. RTLDGLOBAL allows symbols from a loaded library to be visible to all other objects that subsequently load the same library. RTLDLOCAL is useful for situations where you want to control symbol visibility precisely or prevent symbol clashes between different versions of the same library that might be loaded by different parts of an application. It provides a more restrictive scope for library symbol resolution. Using RTLDLOCAL can sometimes lead to unexpected errors if a program relies on symbol visibility that is now restricted. It is often set using the RTLD_LOCAL flag in system calls like dlopen().