From d699b3514c2c9d9fb32b19f487ad648e6fadb814 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Wed, 5 Jun 2019 12:32:07 +0100
Subject: [PATCH] Try to warn if we're running the 32-bit version on 64-bit
 windows (WoW64) (#1569).

---
 src/lib/config.h       |  1 +
 src/lib/cross.cc       | 13 +++++++++++++
 src/lib/cross.h        |  1 +
 src/tools/dcpomatic.cc |  7 +++++++
 4 files changed, 22 insertions(+)

diff --git a/src/lib/config.h b/src/lib/config.h
index e25cb06da..29511b1fe 100644
--- a/src/lib/config.h
+++ b/src/lib/config.h
@@ -377,6 +377,7 @@ public:
 		NAG_INITIAL_SETUP,
 		NAG_IMPORT_DECRYPTION_CHAIN,
 		NAG_DELETE_DKDM,
+		NAG_32_ON_64,
 		NAG_COUNT
 	};
 
diff --git a/src/lib/cross.cc b/src/lib/cross.cc
index 171bf2c81..a7fb298cb 100644
--- a/src/lib/cross.cc
+++ b/src/lib/cross.cc
@@ -501,3 +501,16 @@ command_and_read (string cmd)
 
 	return "";
 }
+
+/** @return true if this process is a 32-bit one running on a 64-bit-capable OS */
+bool
+running_32_on_64 ()
+{
+#ifdef DCPOMATIC_WINDOWS
+	BOOL p;
+	IsWow64Process (GetCurrentProcess(), &p);
+	return p;
+#endif
+	/* XXX: assuming nobody does this on Linux / OS X */
+	return false;
+}
diff --git a/src/lib/cross.h b/src/lib/cross.h
index 06e198e99..2e8b8e429 100644
--- a/src/lib/cross.h
+++ b/src/lib/cross.h
@@ -57,6 +57,7 @@ extern uint64_t thread_id ();
 extern int avio_open_boost (AVIOContext** s, boost::filesystem::path file, int flags);
 extern boost::filesystem::path home_directory ();
 extern std::string command_and_read (std::string cmd);
+extern bool running_32_on_64 ();
 
 /** @class Waker
  *  @brief A class which tries to keep the computer awake on various operating systems.
diff --git a/src/tools/dcpomatic.cc b/src/tools/dcpomatic.cc
index 820289825..96770914d 100644
--- a/src/tools/dcpomatic.cc
+++ b/src/tools/dcpomatic.cc
@@ -1539,6 +1539,13 @@ private:
 				Config::instance()->set_nagged(Config::NAG_INITIAL_SETUP, true);
 			}
 
+			if (running_32_on_64 ()) {
+				NagDialog::maybe_nag (
+					_frame, Config::NAG_32_ON_64,
+					_("You are running the 32-bit version of DCP-o-matic on a 64-bit version of Windows.  This will limit the memory available to DCP-o-matic and may cause errors.  You are strongly advised to install the 64-bit version of DCP-o-matic."),
+					false);
+			}
+
 			_frame->Show ();
 
 			if (!_film_to_load.empty() && boost::filesystem::is_directory (_film_to_load)) {
-- 
2.30.2