[libcamera-devel] [PATCH v2] libcamera: v4l2_device: Fix variable-sized object initialization

[Niklas Söderlund]

Compiling with clang renders errors as a variable-sized arrays are not
allowed to be initialized. Solve this by using memset() for v4l2Ctrls
which is the only one of the two arrays that needs to be zeroed.

    ../../src/libcamera/v4l2_device.cpp:155:37: error: variable-sized object may not be initialized
        const V4L2ControlInfo *controlInfo[count] = {};
                                           ^~~~~
    ../../src/libcamera/v4l2_device.cpp:156:36: error: variable-sized object may not be initialized
	    struct v4l2_ext_control v4l2Ctrls[count] = {};
					      ^~~~~
    ../../src/libcamera/v4l2_device.cpp:227:37: error: variable-sized object may not be initialized
	    const V4L2ControlInfo *controlInfo[count] = {};
					       ^~~~~
    ../../src/libcamera/v4l2_device.cpp:228:36: error: variable-sized object may not be initialized
	    struct v4l2_ext_control v4l2Ctrls[count] = {};
					      ^~~~~
Fixes: eb068f4e67eedacd ("libcamera: v4l2_device: Implement get and set controls")
Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
---
 src/libcamera/v4l2_device.cpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp
index f1821a7ba162e709..e6395341443ce70a 100644
--- a/src/libcamera/v4l2_device.cpp
+++ b/src/libcamera/v4l2_device.cpp
@@ -152,8 +152,10 @@ int V4L2Device::getControls(V4L2ControlList *ctrls)
 	if (count == 0)
 		return 0;
 
-	const V4L2ControlInfo *controlInfo[count] = {};
-	struct v4l2_ext_control v4l2Ctrls[count] = {};
+	const V4L2ControlInfo *controlInfo[count];
+	struct v4l2_ext_control v4l2Ctrls[count];
+	memset(v4l2Ctrls, 0, count * sizeof(v4l2Ctrls[0]));
+
 	for (unsigned int i = 0; i < count; ++i) {
 		const V4L2Control *ctrl = ctrls->getByIndex(i);
 		const V4L2ControlInfo *info = getControlInfo(ctrl->id());
@@ -224,8 +226,9 @@ int V4L2Device::setControls(V4L2ControlList *ctrls)
 	if (count == 0)
 		return 0;
 
-	const V4L2ControlInfo *controlInfo[count] = {};
-	struct v4l2_ext_control v4l2Ctrls[count] = {};
+	const V4L2ControlInfo *controlInfo[count];
+	struct v4l2_ext_control v4l2Ctrls[count];
+	memset(v4l2Ctrls, 0, count * sizeof(v4l2Ctrls[0]));
 
 	for (unsigned int i = 0; i < count; ++i) {
 		const V4L2Control *ctrl = ctrls->getByIndex(i);
-- 
2.21.0