diff --git a/database-plain.c b/database-plain.c
index 3f30c14..8c6bf13 100644
--- a/database-plain.c
+++ b/database-plain.c
@@ -28,7 +28,7 @@
 #define file_lock_set(fd, cmd) \
   { \
   struct flock lock = { .l_type = cmd, .l_start = 0, .l_whence = SEEK_SET, .l_len = 0}; \
-  fcntl(fd, F_SETLK, lock, NULL); \
+  fcntl(fd, F_SETLK, lock); \
   }
 #endif