diff --git a/c/qrcodegen.c b/c/qrcodegen.c
index 8d4a233..e86a1de 100644
--- a/c/qrcodegen.c
+++ b/c/qrcodegen.c
@@ -27,10 +27,16 @@
 #include <string.h>
 #include "qrcodegen.h"
 
-#ifdef QRCODEGEN_TEST
-	#define testable  // Expose private functions
-#else
+#ifndef QRCODEGEN_TEST
 	#define testable static  // Keep functions private
+#else
+	// Expose private functions
+	#ifndef __cplusplus
+		#define testable
+	#else
+		// Needed for const variables because they are treated as implicitly 'static' in C++
+		#define testable extern
+	#endif
 #endif
 
 
diff --git a/c/qrcodegen.h b/c/qrcodegen.h
index ebb80d4..389c523 100644
--- a/c/qrcodegen.h
+++ b/c/qrcodegen.h
@@ -77,10 +77,6 @@ enum qrcodegen_Mask {
 
 /*---- Functions to generate QR Codes ----*/
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /* 
  * Encodes the given text string to a QR Code symbol, returning true if encoding succeeded.
  * If the data is too long to fit in any version in the given range
@@ -144,7 +140,3 @@ int qrcodegen_getSize(const uint8_t qrcode[]);
  * If the given coordinates are out of bounds, then false (white) is returned.
  */
 bool qrcodegen_getModule(const uint8_t qrcode[], int x, int y);
-
-#ifdef __cplusplus
-}
-#endif