Camera board • libcamera::Fence - Does this actually work?

Code:

main(){/// setup setup - works fine// get a real file descriptor from a real file    int _fd = open(filename.c_str(), O_WRONLY | O_TRUNC | O_CREAT );  // returns an int != -1// build the Fence    UniqueFD fd(_fd);    std::unique_ptr<libcamera::Fence> fenceCapture = std::make_unique<libcamera::Fence>(std::forward<UniqueFD>(fd));        std::unique_ptr<Request> requestCapture = camera->createRequest();    if (!requestCapture)    {        std::cerr << "Can't create capture request" << std::endl;        return -ENOMEM;    }// pass the fence into the request with the buffer    ret = requestCapture->addBuffer(streamCapture, buffersCapture[0].get(), std::move(fenceCapture));/// queue requests etc. etc. }

Code:

static void requestComplete(Request *request){// ...    for (auto bufferIterator = std::begin(buffers); bufferIterator != std::end(buffers); bufferIterator++)    {// everything good and the file saves without any problem        png_save(it->second, info, filename);// retrieve the Fence        std::unique_ptr<Fence> bufferFence = bufferIterator->second->releaseFence();        if (bufferFence == nullptr)//<-- always true        {            std::cout << "the buffer fence is null" << std::endl;            return;        }        if (bufferFence->isValid())// <-- segmentation fault if executed            bufferFence->release();        else            std::cout << "Fence is no longer valid" << std::endl;    }// ...}