V4L2 munmap() &manvol; v4l2-munmap Unmap device memory #include <unistd.h> #include <sys/mman.h> int munmap void *start size_t length start Address of the mapped buffer as returned by the &func-mmap; function. length Length of the mapped buffer. This must be the same value as given to mmap() and returned by the driver in the &v4l2-buffer; length field for the single-planar API and in the &v4l2-plane; length field for the multi-planar API. Unmaps a previously with the &func-mmap; function mapped buffer and frees it, if possible. On success munmap() returns 0, on failure -1 and the errno variable is set appropriately: EINVAL The start or length is incorrect, or no buffers have been mapped yet.