diff --git a/libc/include/bits/lockf.h b/libc/include/bits/lockf.h
index ec6e53c..d9f5987 100644
--- a/libc/include/bits/lockf.h
+++ b/libc/include/bits/lockf.h
@@ -56,12 +56,12 @@
  *
  * See also flock().
  */
-int lockf(int __fd, int __cmd, off_t __length) __RENAME_IF_FILE_OFFSET64(lockf64) __INTRODUCED_IN(24);
+int lockf(int __fd, int __op, off_t __length) __RENAME_IF_FILE_OFFSET64(lockf64) __INTRODUCED_IN(24);
 
 /**
  * Like lockf() but allows using a 64-bit length
  * even from a 32-bit process without `_FILE_OFFSET_BITS=64`.
  */
-int lockf64(int __fd, int __cmd, off64_t __length) __INTRODUCED_IN(24);
+int lockf64(int __fd, int __op, off64_t __length) __INTRODUCED_IN(24);
 
 __END_DECLS