diff --git a/src/dpimp.c b/src/dpimp.c
index 544ffbb..cae1777 100644
--- a/src/dpimp.c
+++ b/src/dpimp.c
@@ -486,7 +486,7 @@ main(int argc, char **argv)
     ** small, must respond quickly, and SU mode is more or less guaranteed.
     ** Skip it only if dp_main() already did it for us.
     */
-#if CENV_SYS_DECOSF || CENV_SYS_SOLARIS || CENV_SYS_LINUX
+#if HAVE_MLOCKALL
     if (!(dpimp->dpimp_dpc.dpc_flags & DPCF_MEMLOCK)) {
 	if (mlockall(MCL_CURRENT|MCL_FUTURE) != 0) {
 	    dbprintln("Warning - cannot lock memory");
diff --git a/src/dpni20.c b/src/dpni20.c
index cb09fcd..88980b6 100644
--- a/src/dpni20.c
+++ b/src/dpni20.c
@@ -361,7 +361,7 @@ main(int argc, char **argv)
     ** small, must respond quickly, and SU mode is more or less guaranteed.
     ** Skip it only if dp_main() already did it for us.
     */
-#if CENV_SYS_DECOSF || CENV_SYS_SOLARIS || CENV_SYS_LINUX
+#if HAVE_MLOCKALL
     if (!(dpni->dpni_dpc.dpc_flags & DPCF_MEMLOCK)) {
 	if (mlockall(MCL_CURRENT|MCL_FUTURE) != 0) {
 	    dbprintln("Warning - cannot lock memory");
diff --git a/src/osdsup.c b/src/osdsup.c
index fa73788..9d2ca13 100644
--- a/src/osdsup.c
+++ b/src/osdsup.c
@@ -1679,7 +1679,7 @@ os_memlock(int dolock)
     ** just return error if it fails for any reason.
     */
     if (dolock)
-	return (mlockall(MCL_CURRENT+MCL_FUTURE) == 0);
+	return (mlockall(MCL_CURRENT|MCL_FUTURE) == 0);
     else
 	return (munlockall() == 0);
 #else