7.33. ioctl VIDIOC_G_INPUT, VIDIOC_S_INPUT¶
7.33.1. Name¶
VIDIOC_G_INPUT - VIDIOC_S_INPUT - Query or select the current video input
7.33.2. Synopsis¶
-
int
ioctl(int fd, VIDIOC_G_INPUT, int *argp)¶
-
int
ioctl(int fd, VIDIOC_S_INPUT, int *argp)¶
7.33.4. Description¶
To query the current video input applications call the
VIDIOC_G_INPUT ioctl with a pointer to an integer where the driver
stores the number of the input, as in the struct
v4l2_input index field. This ioctl will fail
only when there are no video inputs, returning EINVAL.
To select a video input applications store the number of the desired input in an integer and call the VIDIOC_S_INPUT ioctl with a pointer to this integer. Side effects are possible. For example inputs may support different video standards, so the driver may implicitly switch the current standard. Because of these possible side effects applications must select an input before querying or negotiating any other parameters.
Information about video inputs is available using the ioctl VIDIOC_ENUMINPUT ioctl.
7.33.5. Return Value¶
On success 0 is returned, on error -1 and the errno variable is set
appropriately. The generic error codes are described at the
Generic Error Codes chapter.
- EINVAL
The number of the video input is out of bounds.