ranlib

Generate index for archive

$ ranlib [libfoo.a]

$ ranlib -U [libfoo.a]

$ ranlib -c [libfoo.a]

$ ranlib [*.a]

ranlib [options] archive...

ranlib generates or updates the symbol table index in a static library archive (.a file), enabling the linker to quickly locate symbols without scanning every object file in the archive. Without this index, the linker must process object files in order and may fail to resolve symbols that appear in a later object file than the one referencing them.
While modern versions of ar automatically create this index when building archives (equivalent to ar -s), ranlib remains useful for regenerating indexes on archives that have been modified or transferred between systems. The -U flag provides an efficient update mode that only rebuilds the index if the archive contents have changed.

-c

Don't warn for old archives.

Deterministic mode.

Update only if needed.

Update timestamps.

Verbose output.

Print version.

Mostly redundant with modern ar. Index may need updating after modifications. Some systems use ar -s instead.

ranlib dates back to early Unix, when archive indexes were not automatically maintained. Part of GNU Binutils, it remains for compatibility though ar now typically handles indexing automatically.

ar(1), nm(1), ld(1), objdump(1)