https://nalar.dev/tags/fcntl/ Recent content in Fcntl on Nalar Hugo en-us Wed, 23 Sep 2026 00:00:00 +0000 https://nalar.dev/fcntl-ofd-locks-follow-open-file-descriptions/ Wed, 23 Sep 2026 00:00:00 +0000 https://nalar.dev/fcntl-ofd-locks-follow-open-file-descriptions/ <p>Traditional POSIX record locks have a property that can surprise code with several descriptors for the same file: lock ownership is associated with the process, and closing a descriptor for that file can release the process&rsquo;s locks on it. Linux open file description locks move ownership to the kernel open file description referenced by a descriptor.</p> <p>The interface still uses <code>fcntl()</code> and <code>struct flock</code>, but the ownership boundary changes. <code>F_OFD_SETLK</code>, <code>F_OFD_SETLKW</code>, and <code>F_OFD_GETLK</code> make byte-range locking track the open file description rather than the process identity.</p>