Messages in this thread | | | From | "Jason L Tibbitts III" <> | Subject | Commit 6016af "[media] v4l2: use __u32 rather than enums in ioctl() structs" breaks C++ users of V4L2 | Date | Mon, 16 Jul 2012 15:40:01 -0500 |
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I ran into problems compiling the program ZoneMinder on Fedora rawhide (currently using something around 3.5rc6) which do not appear with 3.4 kernels. With help this was traced to commit 6016af82eafcb6e086a8f2a2197b46029a843d68, "[media] v4l2: use __u32 rather than enums in ioctl() structs" which changed videodev2.h in a way which appears to be incompatible with C++.
This results in code such as the following: enum v4l2_buf_type type = v4l2_data.fmt.type; failing to compile with: zm_local_camera.cpp:1523:49: error: invalid conversion from '__u32 {aka unsigned int}' to 'v4l2_buf_type' [-fpermissive] but only when compiled with the headers from a 3.5 kernel.
I'm very far from a C++ expert. I talked with some people who do grok it and the issue comes down to restrictions on assignments of ints to enums and additionally that enums in C++ don't have defined size.
- J<
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