diff --git a/cpp/QrCode.cpp b/cpp/QrCode.cpp
index fa5b8fd..ba30176 100644
--- a/cpp/QrCode.cpp
+++ b/cpp/QrCode.cpp
@@ -157,7 +157,7 @@ QrSegment QrSegment::makeEci(long assignVal) {
 
 
 QrSegment::QrSegment(const Mode &md, int numCh, const std::vector<bool> &dt) :
-		mode(md),
+		mode(&md),
 		numChars(numCh),
 		data(dt) {
 	if (numCh < 0)
@@ -166,7 +166,7 @@ QrSegment::QrSegment(const Mode &md, int numCh, const std::vector<bool> &dt) :
 
 
 QrSegment::QrSegment(const Mode &md, int numCh, std::vector<bool> &&dt) :
-		mode(md),
+		mode(&md),
 		numChars(numCh),
 		data(std::move(dt)) {
 	if (numCh < 0)
@@ -177,7 +177,7 @@ QrSegment::QrSegment(const Mode &md, int numCh, std::vector<bool> &&dt) :
 int QrSegment::getTotalBits(const vector<QrSegment> &segs, int version) {
 	int result = 0;
 	for (const QrSegment &seg : segs) {
-		int ccbits = seg.mode.numCharCountBits(version);
+		int ccbits = seg.mode->numCharCountBits(version);
 		if (seg.numChars >= (1L << ccbits))
 			return -1;  // The segment's length doesn't fit the field's bit width
 		if (4 + ccbits > INT_MAX - result)
@@ -210,8 +210,8 @@ bool QrSegment::isNumeric(const char *text) {
 }
 
 
-QrSegment::Mode QrSegment::getMode() const {
-	return mode;
+const QrSegment::Mode &QrSegment::getMode() const {
+	return *mode;
 }
 
 
diff --git a/cpp/QrCode.hpp b/cpp/QrCode.hpp
index 06d661a..9e7f7fc 100644
--- a/cpp/QrCode.hpp
+++ b/cpp/QrCode.hpp
@@ -151,7 +151,7 @@ class QrSegment final {
 	/*---- Instance fields ----*/
 	
 	/* The mode indicator of this segment. Accessed through getMode(). */
-	private: Mode mode;
+	private: const Mode *mode;
 	
 	/* The length of this segment's unencoded data. Measured in characters for
 	 * numeric/alphanumeric/kanji mode, bytes for byte mode, and 0 for ECI mode.
@@ -186,7 +186,7 @@ class QrSegment final {
 	/* 
 	 * Returns the mode field of this segment.
 	 */
-	public: Mode getMode() const;
+	public: const Mode &getMode() const;
 	
 	
 	/*