1ioctl_pipe(2)                 System Calls Manual                ioctl_pipe(2)
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NAME

6       ioctl_pipe - ioctl() operations for General notification mechanism
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SYNOPSIS

9       #include <linux/watch_queue.h>  /* Definition of IOC_WATCH_QUEUE_* */
10       #include <sys/ioctl.h>
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12       int ioctl(int pipefd[1], IOC_WATCH_QUEUE_SET_SIZE, int size);
13       int ioctl(int pipefd[1], IOC_WATCH_QUEUE_SET_FILTER,
14                 struct watch_notification_filter *filter);
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DESCRIPTION

17       The  following ioctl(2) operations are provided to set up general noti‐
18       fication queue parameters.  The notification queue is built on the  top
19       of a pipe(2) opened with the O_NOTIFICATION_PIPE flag.
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21       IOC_WATCH_QUEUE_SET_SIZE (since Linux 5.8)
22              Preallocates  the pipe buffer memory so that it can fit size no‐
23              tification messages.  Currently, size must be between 1 and 512.
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25       IOC_WATCH_QUEUE_SET_FILTER (since Linux 5.8)
26              Watch queue filter can limit events that are received.   Filters
27              are passed in a struct watch_notification_filter and each filter
28              is described by a struct  watch_notification_type_filter  struc‐
29              ture.
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31                  struct watch_notification_filter {
32                          __u32   nr_filters;
33                          __u32   __reserved;
34                          struct watch_notification_type_filter filters[];
35                  };
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37                  struct watch_notification_type_filter {
38                          __u32   type;
39                          __u32   info_filter;
40                          __u32   info_mask;
41                          __u32   subtype_filter[8];
42                  };
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SEE ALSO

45       pipe(2), ioctl(2)
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49Linux man-pages 6.05              2023-05-03                     ioctl_pipe(2)
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