int ioctl(int fd, int request = FE_READ_SIGNAL_STRENGTH, uint16_t *strength) Arguments

int fd File descriptor returned by a previous call to open().
int request Equals FE_READ_SIGNAL_STRENGTH for this command.
uint16_t *strength The signal strength value is stored into *strength. Description

This ioctl call returns the signal strength value for the signal currently received by the front-end. For this command, read-only access to the device is sufficient. 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.