diff --git a/libc/sysv/consts.sh b/libc/sysv/consts.sh
index f0af04e88..47cdd9b00 100755
--- a/libc/sysv/consts.sh
+++ b/libc/sysv/consts.sh
@@ -265,6 +265,7 @@ syscon	madv	MADV_FREE				8			8			5			5			5			6			6			8			# Linux 4.5+ (c. 2016)
 syscon	madv	MADV_HUGEPAGE				14			14			127			127			127			127			127			127			# TODO(jart): why would we need it?
 syscon	madv	MADV_NOHUGEPAGE				15			15			127			127			127			127			127			127			# TODO(jart): why would we need it?
 syscon	madv	MADV_DODUMP				17			17			127			127			127			127			127			127			# TODO(jart): what is it?
+syscon	madv	MADV_WIPEONFORK				18			18			127			127			127			127			127			127			# TODO: add support ?
 syscon	madv	MADV_DOFORK				11			11			127			127			127			127			127			127			# TODO(jart): what is it?
 syscon	madv	MADV_DONTDUMP				16			16			127			127			127			127			127			127			# see MAP_CONCEAL in OpenBSD; TODO(jart): what is it?
 syscon	madv	MADV_DONTFORK				10			10			127			127			127			127			127			127			# TODO(jart): what is it?
diff --git a/libc/sysv/consts/MADV_WIPEONFORK.S b/libc/sysv/consts/MADV_WIPEONFORK.S
new file mode 100644
index 000000000..1ffaff64e
--- /dev/null
+++ b/libc/sysv/consts/MADV_WIPEONFORK.S
@@ -0,0 +1,2 @@
+#include "libc/sysv/consts/syscon.internal.h"
+.syscon madv,MADV_WIPEONFORK,18,18,127,127,127,127,127,127
diff --git a/libc/sysv/consts/madv.h b/libc/sysv/consts/madv.h
index 189ae1a80..90266929b 100644
--- a/libc/sysv/consts/madv.h
+++ b/libc/sysv/consts/madv.h
@@ -20,6 +20,7 @@ extern const unsigned MADV_SEQUENTIAL;
 extern const unsigned MADV_UNMERGEABLE;
 extern const unsigned MADV_WILLNEED;
 extern const unsigned MADV_SOFT_OFFLINE;
+extern const unsigned MADV_WIPEONFORK;
 
 #define MADV_NORMAL     0
 #define MADV_RANDOM     1