Function queue_buffer

rustcv-camera/src/backend/linux/sys.rs:288–297

Enqueue a buffer — return it to the driver for filling (VIDIOC_QBUF). 将缓冲区入队 —— 归还给驱动以便其写入新数据（VIDIOC_QBUF）。

(fd: RawFd, index: u32)

/// Enqueue a buffer — return it to the driver for filling (VIDIOC_QBUF).
/// 将缓冲区入队 —— 归还给驱动以便其写入新数据（VIDIOC_QBUF）。
pub fn queue_buffer(fd: RawFd, index: u32) -> io::Result<()> {
    let mut buf: v4l2_buffer = unsafe { std::mem::zeroed() };
    buf.index = index;
    buf.type_ = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    buf.memory = V4L2_MEMORY_MMAP;
    unsafe {
        v4l2_ioctl(fd, VIDIOC_QBUF, &mut buf as *mut _ as *mut libc::c_void)?;
    }
    Ok(())
}

/// Dequeue a buffer — retrieve a filled buffer from the driver (VIDIOC_DQBUF).
/// 将缓冲区出队 —— 从驱动取回已写满数据的缓冲区（VIDIOC_DQBUF）。