DTRUNPATH

DTRUNPATH is the runtime path tag used by the ELF dynamic linker to locate shared libraries. In ELF binaries, it corresponds to the DT_RUNPATH entry in the dynamic section, and it specifies directories to be searched for dependencies at program startup and during dynamic loading.

Purpose and behavior: DTRUNPATH directs the linker to search the listed directories for needed libraries. Compared with DT_RPATH, RUNPATH is designed to cooperate with the LD_LIBRARY_PATH environment variable, allowing runtime paths to be augmented by user-supplied paths. If both are present, RUNPATH is consulted in a way that permits LD_LIBRARY_PATH to influence the effective search path.

Setting DTRUNPATH: Most linkers provide options to embed a runpath into the resulting binary, for example by using linker flags to specify runpath directories at link time. This approach promotes relocatability of binaries and packages where libraries are installed in non-default locations, helping to ensure that dependencies can be found without requiring system-wide changes.

Platform notes: DTRUNPATH is specific to ELF-based systems such as Linux and many BSD variants; macOS uses a different mechanism for locating libraries and does not use DT_RUNPATH. In practice, the presence of a runpath can aid packaging tools and distribution maintainers by making binaries more self-contained with respect to their library dependencies.

See also: DT_RUNPATH, DT_RPATH, LD_LIBRARY_PATH, dynamic linker, ELF, shared libraries.