systemd sd-dlopen 3 sd-dlopen ELF dlopen metadata annotation macros #include <systemd/sd-dlopen.h> pkg-config --cflags libsystemd sd-dlopen.h provides macros for embedding .note.dlopen metadata in ELF binaries, implementing the ELF dlopen metadata specification for declaring optional shared library dependencies that are loaded via dlopen3 at runtime. The header is self-contained and does not require runtime linkage against libsystemd3. Projects only need the installed header to use the macros. Package managers and build systems can read the embedded ELF notes to discover runtime dependencies that are not visible in ELF DT_NEEDED entries. See SD_ELF_NOTE_DLOPEN3 for details on the available macros and constants. The macros described here are header-only and do not require runtime linkage against libsystemd3. Only the installed header and include path (as provided by pkg-config --cflags libsystemd) are needed. SD_ELF_NOTE_DLOPEN() and associated macros and constants were added in version 261. systemd1 SD_ELF_NOTE_DLOPEN3 dlopen3