Name
ioctl_pipe - ioctl() operations for General notification mechanismSynopsis
"#include <linux/watch_queue.h>" " /* Definition of " IOC_WATCH_QUEUE_ "* */"#include <sys/ioctl.h> int ioctl(int " pipefd "[1], IOC_WATCH_QUEUE_SET_SIZE, int size );
int ioctl(int " pipefd "[1], IOC_WATCH_QUEUE_SET_FILTER,
struct watch_notification_filter * filter );
Description
The following ioctl(2) operations are provided to set up general notification queue parameters. The notification queue is built on the top of a pipe(2) opened with the O_NOTIFICATION_PIPE flag.IOC_WATCH_QUEUE_SET_SIZE (since Linux 5.8)
Preallocates the pipe buffer memory so that it can fit size notification messages. Currently, size must be between 1 and 512.
IOC_WATCH_QUEUE_SET_FILTER (since Linux 5.8)
Watch queue filter can limit events that are received. Filters are passed in a struct watch_notification_filter and each filter is described by a struct watch_notification_type_filter structure.
struct watch_notification_filter {
__u32 nr_filters;
__u32 __reserved;
struct watch_notification_type_filter filters[];
};
struct watch_notification_type_filter {
__u32 type;
__u32 info_filter;
__u32 info_mask;
__u32 subtype_filter[8];
};