RTLDDEFAULT

RTLDDEFAULT is a dynamic linker option that allows the operating system to select a default library to be used when no specific library is specified for a binary. This option is typically used in the linkers of various operating systems, including Linux, to provide a mechanism to override the default behavior of the dynamic linker.

In Linux systems, RTLDDEFAULT is specified by the interpreter/loader of the library, known as dlopen(). The option is used to specify a base library to be used as a default when no explicit dependency is specified for a binary. When RTLDDEFAULT is used, the dynamic linker searches for the specified library at runtime and loads it before attempting to run the binary. This allows the library to provide shared functions or variables that can be used by the binary.

RTLDDEFAULT is commonly used in combination with the LD_LIBRARY_PATH environment variable to change the search path for dynamic libraries. The interpreter/loader is responsible for resolving the symbols in the libraries specified in RTLDDEFAULT and LD_LIBRARY_PATH.

When a binary is executed, the dynamic linker searches for the libraries specified in RTLDDEFAULT and loads the first one it finds. The binary can then use the functions and variables provided by this library. RTLDDEFAULT can also be used to enforce a specific version of a library, by specifying the full path to the library. This is useful for applications that require a specific version of a library to function correctly.

RTLDDEFAULT is a flexible tool for controlling the dynamic linking behavior of binaries, and is widely used in Linux systems to manage dependencies and compatibility issues.