doc: outline usage

1 files changed, 6 insertions, 1 deletions

diff --git a/sid.mli b/sid.mli
index a21c5ec..de9d6ea 100644
--- a/sid.mli
+++ b/sid.mli
@@ -4,7 +4,12 @@
 
     {e Sid} implements the “Security Identifier” data type commonly used
     on the Microsoft Windows platform. When processing input, it tries to
-    adhere as closely to the specification as possible.
+    adhere as closely to the specification as possible. Optionally, a
+    special mode for the text representation is available as the
+    {e MSStringFmt} module which aims to be bug-for-bug compatible with
+    the official implementation. There is no such mode for the two identical
+    binary representations due to the fact that they don’t leave room for
+    ambiguity.
 
     @see <https://msdn.microsoft.com/en-us/library/cc230371.aspx> the relevant
     section in the {e [MS-DTYP]} compilation of types. *)