From 0507674a13a02a46c789b6e314deffb73302e135 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jean-Fran=C3=A7ois=20Roche?= <jfroche@pyxel.be>
Date: Tue, 4 Nov 2025 20:56:15 +0000
Subject: [PATCH] Document the new cleanup function using a Doxygen-style
 comment

---
 src/libstore/unix/build/darwin-derivation-builder.cc | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/libstore/unix/build/darwin-derivation-builder.cc b/src/libstore/unix/build/darwin-derivation-builder.cc
index 701da9513..613ec6d54 100644
--- a/src/libstore/unix/build/darwin-derivation-builder.cc
+++ b/src/libstore/unix/build/darwin-derivation-builder.cc
@@ -227,6 +227,15 @@ struct DarwinDerivationBuilder : DerivationBuilderImpl
             NULL, drv.builder.c_str(), NULL, &attrp, stringsToCharPtrs(args).data(), stringsToCharPtrs(envStrs).data());
     }
 
+    /**
+     * Cleans up all System V IPC objects owned by the specified user.
+     *
+     * On Darwin, IPC objects (shared memory segments, message queues, and semaphore)
+     * can persist after the build user's processes are killed, since there are no IPC namespaces
+     * like on Linux. This can exhaust kernel IPC limits over time.
+     *
+     * Uses sysctl to enumerate and remove all IPC objects owned by the given UID.
+     */
     void cleanupSysVIPCForUser(uid_t uid)
     {
         struct IpcsCommand ic;