ADLINK Technology cRTV-24, User Manual

Page: 172 / 178

162 Programming Guide
Read frame
Read frame image when an image was ready and prepare next
frame.
Int read_frame (void)
{
struct v4l2_buffer buf;
memset (&buf, 0, sizeof (buf));
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
/* read frame */
if (-1 == ioctl (fd, VIDIOC_DQBUF, &buf)) {
switch (errno) {
case EAGAIN:
return 0;
case EIO:
/* Could ignore EIO, see spec. */
/* fall through */
default:
exit (EXIT_FAILURE);
}
}
/* prepare next frame */
if (-1 == ioctl (fd, VIDIOC_QBUF, &buf))
exit (EXIT_FAILURE);
return 0;
}