The types pthread_rwlock_t, pthread_rwlockattr_t, pthread_barrier_t, pthread_barrierattr_t are unions in the glibc headers, but structs in druntime. As a result they are bigger in druntime.
Found by comparing type sizes in druntime with type sizes found with ImportC: https://github.com/dlang/dmd/pull/16571
Comment #1 by robert.schadek — 2024-12-07T13:43:36Z