1 files changed, 10 insertions, 1 deletions

diff --git a/lib/libc/gen/setmode.3 b/lib/libc/gen/setmode.3
index 4c85b30e2a383..bc38fd3e11938 100644
--- a/lib/libc/gen/setmode.3
+++ b/lib/libc/gen/setmode.3
@@ -81,10 +81,19 @@ is to modify future file modes correctly.
 .Pp
 If the mode passed to
 .Fn setmode
-is invalid,
+is invalid or if memory cannot be allocated for the return value,
 .Fn setmode
 returns
 .Dv NULL . 
+.Pp
+The value returned from 
+.Fn setmode 
+is obtained from 
+.Fn malloc 
+and should be returned to the system with
+.Fn free 
+when the program is done with it, generally after a call to 
+.Fn getmode .  
 .Sh ERRORS
 The
 .Fn setmode