directio
diff --git a/src/os/unix/ngx_files.h b/src/os/unix/ngx_files.h
index 0c080c4..62af63b 100644
--- a/src/os/unix/ngx_files.h
+++ b/src/os/unix/ngx_files.h
@@ -189,4 +189,22 @@
#define ngx_unlock_fd_n "fcntl(F_SETLK, F_UNLCK)"
+#if (NGX_HAVE_O_DIRECT)
+
+ngx_int_t ngx_directio(ngx_fd_t fd);
+#define ngx_directio_n "fcntl(O_DIRECT)"
+
+#elif (NGX_HAVE_F_NOCACHE)
+
+#define ngx_directio(fd) fcntl(fd, F_NOCACHE, 1)
+#define ngx_directio_n "fcntl(F_NOCACHE)"
+
+#else
+
+#define ngx_directio(fd) 0
+#define ngx_directio_n "ngx_directio_n"
+
+#endif
+
+
#endif /* _NGX_FILES_H_INCLUDED_ */
