Index: head/lib/libc/sys/pipe.2
===================================================================
--- head/lib/libc/sys/pipe.2
+++ head/lib/libc/sys/pipe.2
@@ -28,7 +28,7 @@
 .\"     @(#)pipe.2	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd June 22, 2016
+.Dd July 20, 2016
 .Dt PIPE 2
 .Os
 .Sh NAME
@@ -109,6 +109,18 @@
 portable to older systems, so it is recommended to use the convention
 for using the endpoints in the traditional manner when using a
 pipe in one direction.
+.Sh IMPLEMENTATION NOTES
+The
+.Fn pipe
+function calls the
+.Fn pipe2
+system call.
+As a result, system call traces such as those captured by
+.Xr dtrace 1
+or
+.Xr ktrace 1
+will show calls to
+.Fn pipe2 .
 .Sh RETURN VALUES
 .Rv -std pipe
 .Sh ERRORS
@@ -157,3 +169,10 @@
 .Fn pipe2
 function appeared in
 .Fx 10.0 .
+.Pp
+The
+.Fn pipe
+function became a wrapper around
+.Fn pipe2
+in
+.Fx 11.0 .