From f1eede1106c710e498deea2640fb3981204408b3 Mon Sep 17 00:00:00 2001
From: Eric Fischer <enf@pobox.com>
Date: Tue, 13 Mar 2018 15:04:28 -0700
Subject: [PATCH] Track the last progress update with an atomic type, not
 volatile

---
 main.cpp | 2 +-
 main.hpp | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/main.cpp b/main.cpp
index af2fd23..5f2760f 100644
--- a/main.cpp
+++ b/main.cpp
@@ -68,7 +68,7 @@ static int min_detail = 7;
 int quiet = 0;
 int quiet_progress = 0;
 double progress_interval = 0;
-volatile double last_progress = 0;
+std::atomic<double> last_progress(0);
 int geometry_scale = 0;
 double simplification = 1;
 size_t max_tile_size = 500000;
diff --git a/main.hpp b/main.hpp
index 7e3c647..9a74a92 100644
--- a/main.hpp
+++ b/main.hpp
@@ -2,6 +2,7 @@
 #define MAIN_HPP
 
 #include <stddef.h>
+#include <atomic>
 
 struct index {
 	long long start = 0;
@@ -23,7 +24,7 @@ extern int geometry_scale;
 extern int quiet;
 extern int quiet_progress;
 extern double progress_interval;
-extern volatile double last_progress;
+extern std::atomic<double> last_progress;
 
 extern size_t CPUS;
 extern size_t TEMP_FILES;