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

VIDIOC_G_INPUT

int ioctl(int fd, VIDIOC_G_INPUT, int *argp)

VIDIOC_S_INPUT

int ioctl(int fd, VIDIOC_S_INPUT, int *argp)

7.33.3. Arguments

fd

File descriptor returned by open().

argp

Pointer an integer with input index.

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.