From 67c31d794e3eea00af7f4a38965cf8a38a6f1f72 Mon Sep 17 00:00:00 2001
From: Howard Hinnant <howard.hinnant@gmail.com>
Date: Sat, 28 May 2016 14:09:46 -0400
Subject: [PATCH] Protect undocumented constructors

---
 tz.cpp | 13 +++++++++----
 tz.h   |  9 +++++++--
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/tz.cpp b/tz.cpp
index 1efadbe..1ed7132 100644
--- a/tz.cpp
+++ b/tz.cpp
@@ -126,6 +126,11 @@ CONSTDATA auto max_day = date::dec/31;
 // | End Configuration |
 // +-------------------+
 
+namespace detail
+{
+class undocumented {explicit undocumented() = default;};
+}
+
 #ifndef _MSC_VER
 static_assert(min_year <= max_year, "Configuration error");
 #endif
@@ -1262,7 +1267,7 @@ time_zone::zonelet::zonelet(const zonelet& i)
 #endif
 }
 
-time_zone::time_zone(const std::string& s)
+time_zone::time_zone(const std::string& s, detail::undocumented)
 #if LAZY_INIT
     : adjusted_(new std::once_flag{})
 #endif
@@ -1923,7 +1928,7 @@ operator<<(std::ostream& os, const Link& x)
 
 // Leap
 
-Leap::Leap(const std::string& s)
+Leap::Leap(const std::string& s, detail::undocumented)
 {
     using namespace date;
     std::istringstream in(s);
@@ -2146,12 +2151,12 @@ init_tzdb()
                 }
                 else if (word == "Leap")
                 {
-                    db.leaps.push_back(Leap(line));
+                    db.leaps.push_back(Leap(line, detail::undocumented{}));
                     continue_zone = false;
                 }
                 else if (word == "Zone")
                 {
-                    db.zones.push_back(time_zone(line));
+                    db.zones.push_back(time_zone(line, detail::undocumented{}));
                     continue_zone = true;
                 }
                 else if (line[0] == '\t' && continue_zone)
diff --git a/tz.h b/tz.h
index 8bbe912..ee9dde3 100644
--- a/tz.h
+++ b/tz.h
@@ -99,6 +99,11 @@ namespace date
 
 enum class choose {earliest, latest};
 
+namespace detail
+{
+    class undocumented;
+}
+
 class nonexistent_local_time
     : public std::runtime_error
 {
@@ -321,7 +326,7 @@ public:
     time_zone& operator=(time_zone&& src);
 #endif  // defined(_MSC_VER) && (_MSC_VER < 1900)
 
-    explicit time_zone(const std::string& s);
+    explicit time_zone(const std::string& s, detail::undocumented);
 
     const std::string& name() const;
 
@@ -517,7 +522,7 @@ private:
     sys_seconds date_;
 
 public:
-    explicit Leap(const std::string& s);
+    explicit Leap(const std::string& s, detail::undocumented);
 
     sys_seconds date() const {return date_;}