diff --git a/lib/std/mem.zig b/lib/std/mem.zig
index 278e917df6213af76dbd1131d7acc872416fbe30..a679291dba1bcae6e79286ad3b7b199562f68695 100644
--- a/lib/std/mem.zig
+++ b/lib/std/mem.zig
@@ -269,8 +269,10 @@ pub fn copyBackwards(comptime T: type, dest: []T, source: []const T) void {
     }
 }
 
-/// Copy `source` into `dest`. Asserts no overlap. Asserts `dest.len` greater or equal to source len. Returns
-/// number of elements copied. Sentinel is not copied.
+/// Copy `source` into `dest`, excluding the sentinel.
+///
+/// Asserts no overlap. Asserts `dest.len` greater or equal to source len. Returns number of elements copied,
+/// not counting the sentinel.
 pub fn copySentinel(comptime T: type, comptime s: T, dest: []T, source: [*:s]const T) usize {
     const i = findSentinel(T, s, source);
     @memcpy(dest[0..i], source[0..i]);
@@ -284,6 +286,22 @@ test copySentinel {
     try testing.expectEqual(n, 10);
 }
 
+/// Copy `source` into `dest`, including the sentinel.
+///
+/// Asserts no overlap. Asserts `dest.len` greater or equal to source len, including room for the sentinel.
+/// Returns number of elements copied, including the sentinel.
+pub fn copySentinelInclusive(comptime T: type, comptime s: T, dest: []T, source: [*:s]const T) usize {
+    const i = findSentinel(T, s, source) + 1;
+    @memcpy(dest[0..i], source[0..i]);
+    return i;
+}
+
+test copySentinelInclusive {
+    var dst: [12]u8 = @splat(0xff);
+    const n = copySentinelInclusive(u8, 0, &dst, "hello this\x00is my null-terminated string");
+    try testing.expectEqualStrings("hello this\x00\xff", &dst);
+    try testing.expectEqual(n, 11);
+}
 /// Generally, Zig users are encouraged to explicitly initialize all fields of a struct explicitly rather than using this function.
 /// However, it is recognized that there are sometimes use cases for initializing all fields to a "zero" value. For example, when
 /// interfacing with a C API where this practice is more common and relied upon. If you are performing code review and see this