7.32. ioctl VIDIOC_G_FREQUENCY, VIDIOC_S_FREQUENCY¶
VIDIOC_G_FREQUENCY - VIDIOC_S_FREQUENCY - Get or set tuner or modulator radio frequency
int ioctl(int fd, VIDIOC_G_FREQUENCY, struct v4l2_frequency *argp)
int ioctl(int fd, VIDIOC_S_FREQUENCY, const struct v4l2_frequency *argp)
File descriptor returned by
Pointer to struct
To get the current tuner or modulator radio frequency applications set
tuner field of a struct
v4l2_frequency to the respective tuner or
modulator number (only input devices have tuners, only output devices
have modulators), zero out the
reserved array and call the
VIDIOC_G_FREQUENCY ioctl with a pointer to this structure. The
driver stores the current frequency in the
To change the current tuner or modulator radio frequency applications
frequency fields, and the
reserved array of a struct
and call the VIDIOC_S_FREQUENCY ioctl with a pointer to this
structure. When the requested frequency is not possible the driver
assumes the closest possible value. However VIDIOC_S_FREQUENCY is a
write-only ioctl, it does not return the actual new frequency.
The tuner or modulator index number. This is the same value as in
The tuner type. This is the same value as in the struct
Tuning frequency in units of 62.5 kHz, or if the struct
Reserved for future extensions. Drivers and applications must set the array to zero.
7.32.5. 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.
tunerindex is out of bounds or the value in the
typefield is wrong.
A hardware seek is in progress.