Documentation for randint. Better randomness defaults. Fixes: #722

[exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index b640daec638fb5f928523ca79ce4185298ec7da5..bf7a987b9eba7b0d34b37415a56745048098ce38 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -1,4 +1,4 @@
-. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.68 2009/11/16 19:10:45 nm4 Exp $
+. $Cambridge: exim/doc/doc-docbook/spec.xfpt,v 1.69 2009/11/16 19:15:36 nm4 Exp $
 .
 . /////////////////////////////////////////////////////////////////////////////
 . This is the primary source of the Exim Manual. It is an xfpt document that is
@@ -9589,6 +9589,17 @@ For single-key lookup types, no quoting is ever necessary and this operator
 yields an unchanged string.
 
 
+.vitem &*${randint:*&<&'n'&>&*}*&
+.cindex "random number"
+This operator returns a somewhat random number which is less than the
+supplied number and is at least 0.  The quality of this randomness depends
+on how Exim was built; the values are not suitable for keying material.
+If Exim is linked against OpenSSL then RAND_pseudo_bytes() is used.
+Otherwise, the implementation may be arc4random(), random() seeded by
+srandomdev() or srandom(), or a custom implementation even weaker than
+random().
+
+
 .vitem &*${rfc2047:*&<&'string'&>&*}*&
 .cindex "expansion" "RFC 2047"
 .cindex "RFC 2047" "expansion operator"