From 2946455cd16d2205caa270924b844ad47c78d1ff Mon Sep 17 00:00:00 2001
From: Jesse Williamson <nerd.cpp@gmail.com>
Date: Tue, 3 Sep 2019 18:25:36 -0700
Subject: [PATCH] common: random: added a deduction guide to make using the
 function object interface a bit nicer to use.

Signed-off-by: Jesse Williamson <nerd.cpp@gmail.com>
---
 src/include/random.h           |  7 +++++--
 src/test/common/test_random.cc | 11 +++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/include/random.h b/src/include/random.h
index b3cb80c31d2..0501a878049 100644
--- a/src/include/random.h
+++ b/src/include/random.h
@@ -20,10 +20,10 @@
 #include <type_traits>
 #include <boost/optional.hpp>
 
-// Basic random number facility, adapted from N3551:
+// Basic random number facility (see N3551 for inspiration):
 namespace ceph::util {
 
-inline namespace version_1_0_2 {
+inline namespace version_1_0_3 {
 
 namespace detail {
 
@@ -282,6 +282,9 @@ class random_number_generator final
   }
 };
 
+template <typename NumberT>
+random_number_generator(const NumberT max) -> random_number_generator<NumberT>;
+
 } // inline namespace version_*
 
 } // namespace ceph::util
diff --git a/src/test/common/test_random.cc b/src/test/common/test_random.cc
index 85bb732b475..14d13ca7e12 100644
--- a/src/test/common/test_random.cc
+++ b/src/test/common/test_random.cc
@@ -200,6 +200,17 @@ TEST(util, test_random_class_interface)
     ceph::util::random_number_generator<int> rng(1234);   // seed
   }
  
+  // Test deduction guides:
+  {
+    { ceph::util::random_number_generator rng(1234); }
+    { ceph::util::random_number_generator rng(1234.1234); }
+
+    {
+    int x = 1234;
+    ceph::util::random_number_generator rng(x);
+    }
+  }
+
   {
     int a = rng_i();
     int b = rng_i();
-- 
2.39.5