README.md

Userspace RCU list headers

diffofdiffs uses Userspace RCU's intrusive lists without any RCU APIs or library linkage. These headers remove the need to install liburcu to build diffofdiffs.

The source is Userspace RCU v0.15.7, commit bbc6bc94901aebe6380e4e798858b995a8d3fd5d:

• list.h is an unmodified copy of upstream include/urcu/list.h
• compiler.h keeps the copyright notice, include guard, <stddef.h> include, and caa_container_of definition from upstream include/urcu/compiler.h
• LICENSE is an unmodified copy of upstream LICENSES/LGPL-2.1-or-later.txt

The compiler.h subset was extracted on 2026-09-23. Its other helpers and includes were omitted so that list.h doesn't pull in liburcu's generated configuration header. The retained macro is unchanged, including its argument type check and single evaluation of the input pointer. The subset adds a notice describing the extraction and omits the original header description and the <stddef.h> include comment. Using other Userspace RCU headers requires an explicit update to the bundled subset.

Both headers retain their upstream LGPL-2.1-or-later license and copyright notices. Keep their formatting when updating them. To update, replace list.h and LICENSE from a pinned upstream revision, refresh the compiler.h subset, and record the new revision and any local changes here. Run make check and make check-asan, and verify a clean build with the system liburcu headers unavailable.

To check the header dependencies without changing system packages:

printf '#include <urcu/list.h>\n' | cc -std=gnu17 -Ivendor -M -x c -

Run this from the project root. The output should name vendor/urcu/list.h and vendor/urcu/compiler.h, with no system urcu headers or urcu/config.h.