diff --git a/src/usb_libusb10.c b/src/usb_libusb10.c
index 11de86a8..614aeeeb 100644
--- a/src/usb_libusb10.c
+++ b/src/usb_libusb10.c
@@ -465,6 +465,7 @@ FN_INTERNAL int fnusb_open_subdevices(freenect_device *dev, int index)
 	}
 	
 	if (res < 0 || camera == NULL) {
+		res = -1;
 		goto failure;
 	}
 
diff --git a/wrappers/c_sync/libfreenect_sync.c b/wrappers/c_sync/libfreenect_sync.c
index 1b2e0494..26a2261c 100644
--- a/wrappers/c_sync/libfreenect_sync.c
+++ b/wrappers/c_sync/libfreenect_sync.c
@@ -249,7 +249,7 @@ static int change_depth_format(sync_kinect_t *kinect, freenect_resolution res, f
 static sync_kinect_t *alloc_kinect(int index)
 {
 	sync_kinect_t *kinect = (sync_kinect_t*)malloc(sizeof(sync_kinect_t));
-	if (freenect_open_device(ctx, &kinect->dev, index)) {
+	if (freenect_open_device(ctx, &kinect->dev, index) < 0) {
 		free(kinect);
 		return NULL;
 	}
diff --git a/wrappers/opencv/CMakeLists.txt b/wrappers/opencv/CMakeLists.txt
index 02390752..bc5df19b 100644
--- a/wrappers/opencv/CMakeLists.txt
+++ b/wrappers/opencv/CMakeLists.txt
@@ -2,7 +2,7 @@
 # OpenCV Interface
 ######################################################################################
 find_package(OpenCV REQUIRED)
-add_library (freenect_cv SHARED libfreenect_cv.c)
+add_library (freenect_cv SHARED libfreenect_cv.cpp)
 set_target_properties (freenect_cv PROPERTIES
   VERSION ${PROJECT_VER}
   SOVERSION ${PROJECT_APIVER})
@@ -16,7 +16,7 @@ install (TARGETS freenect_cv
 install (FILES "libfreenect_cv.h"
   DESTINATION ${PROJECT_INCLUDE_INSTALL_DIR})
 
-add_executable(freenect-cvdemo cvdemo.c)
+add_executable(freenect-cvdemo cvdemo.cpp)
 target_link_libraries(freenect-cvdemo freenect freenect_sync freenect_cv ${OpenCV_LIBS})
 install (TARGETS freenect-cvdemo
   DESTINATION bin)
diff --git a/wrappers/opencv/cvdemo.c b/wrappers/opencv/cvdemo.cpp
similarity index 100%
rename from wrappers/opencv/cvdemo.c
rename to wrappers/opencv/cvdemo.cpp
diff --git a/wrappers/opencv/libfreenect_cv.c b/wrappers/opencv/libfreenect_cv.cpp
similarity index 100%
rename from wrappers/opencv/libfreenect_cv.c
rename to wrappers/opencv/libfreenect_cv.cpp
diff --git a/wrappers/opencv/libfreenect_cv.h b/wrappers/opencv/libfreenect_cv.h
index b73b60c9..55e3582c 100644
--- a/wrappers/opencv/libfreenect_cv.h
+++ b/wrappers/opencv/libfreenect_cv.h
@@ -1,11 +1,11 @@
 #pragma once
 
+#include <opencv/cv.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#include <opencv/cv.h>
-
 	IplImage *freenect_sync_get_depth_cv(int index);
 	IplImage *freenect_sync_get_rgb_cv(int index);