diff --git a/include/sys/svrctl.h b/include/sys/svrctl.h
index 90291897b..9df1a4aca 100755
--- a/include/sys/svrctl.h
+++ b/include/sys/svrctl.h
@@ -19,6 +19,7 @@ Created:	Feb 15, 1994 by Philip Homburg <philip@cs.vu.nl>
 #define MMSWAPON	_IOW('M',  5, struct mmswapon)
 #define MMSWAPOFF	_IO ('M',  6)
 #define MMGETPARAM	_IOW('M',  5, struct sysgetenv)
+#define MMSETPARAM	_IOR('M',  7, struct sysgetenv)
 
 /* FS controls. */
 #define FSSIGNON	_IOW('F',  2, struct fssignon)