diff --git a/lib/std/c/netbsd.zig b/lib/std/c/netbsd.zig
index 8f3837b2bb..2c7c236ed0 100644
--- a/lib/std/c/netbsd.zig
+++ b/lib/std/c/netbsd.zig
@@ -579,6 +579,12 @@ pub const PROT = struct {
     pub const READ = 1;
     pub const WRITE = 2;
     pub const EXEC = 4;
+    pub fn MPROTECT(flag: u32) u32 {
+        return flag << 3;
+    }
+    pub fn MPROTECT_EXTRACT(flag: u32) u32 {
+        return (flag >> 3) & 0x7;
+    }
 };
 
 pub const CLOCK = struct {
@@ -621,6 +627,16 @@ pub const MAP = struct {
     pub const ALIGNMENT_64PB = MAP.ALIGNED(56);
 };
 
+pub const MADV = struct {
+    pub const NORMAL = 0;
+    pub const RANDOM = 1;
+    pub const SEQUENTIAL = 2;
+    pub const WILLNEED = 3;
+    pub const DONTNEED = 4;
+    pub const SPACEAVAIL = 5;
+    pub const FREE = 6;
+};
+
 pub const MSF = struct {
     pub const ASYNC = 1;
     pub const INVALIDATE = 2;
diff --git a/lib/std/c/openbsd.zig b/lib/std/c/openbsd.zig
index 4d44461237..47c1aec862 100644
--- a/lib/std/c/openbsd.zig
+++ b/lib/std/c/openbsd.zig
@@ -466,6 +466,16 @@ pub const MAP = struct {
     pub const CONCEAL = 0x8000;
 };
 
+pub const MADV = struct {
+    pub const NORMAL = 0;
+    pub const RANDOM = 1;
+    pub const SEQUENTIAL = 2;
+    pub const WILLNEED = 3;
+    pub const DONTNEED = 4;
+    pub const SPACEAVAIL = 5;
+    pub const FREE = 6;
+};
+
 pub const MSF = struct {
     pub const ASYNC = 1;
     pub const INVALIDATE = 2;