doc sub srand

Author: gfldex

doc/Type/Num.pod6

@@ -17,4 +17,12 @@ float point not-a-number value. It is defined and boolifies to True. C<NaN> is
 the result of undefined float point number operations and depends on the CPU or
 software implementation of float point numbers on the system running the code.
 
+=head2 sub srand
+
+    sub srand(Int $seed) returns Int:D
+
+Seeds the pseudo random number generator used by L<Num.rand|/typeNum#rand) with
+the provided value. Note that C<srand> is called with a platform dependent
+value when a Perl 6 program is started.
+
 =end pod