diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/libc/sys/kqueue.2 | 54 |
1 files changed, 44 insertions, 10 deletions
diff --git a/lib/libc/sys/kqueue.2 b/lib/libc/sys/kqueue.2 index 1787a6e..b05833d 100644 --- a/lib/libc/sys/kqueue.2 +++ b/lib/libc/sys/kqueue.2 @@ -41,6 +41,7 @@ .Fn kqueue "void" .Ft int .Fn kevent "int kq" "const struct kevent *changelist" "int nchanges" "struct kevent *eventlist" "int nevents" "const struct timespec *timeout" +.Fn EV_SET "&kev" ident filter flags fflags data udata .Sh DESCRIPTION .Fn kqueue provides a generic method of notifying the user when an event @@ -114,6 +115,10 @@ structure. The same array may be used for the and .Fa eventlist . .Pp +.Fn EV_SET +is a macro which is provided for ease of initializing a +kevent structure. +.Pp The .Va kevent structure is defined as: @@ -199,6 +204,7 @@ Takes a descriptor as the identifier, and returns whenever there is data available to read. The behavior of the filter is slightly different depending on the descriptor type. +.Pp .Bl -tag -width 2n .It Sockets Sockets which have previously been passed to @@ -208,13 +214,25 @@ return when there is an incoming connection pending. contains the size of the listen backlog. .Pp Other socket descriptors return when there is data to be read, -subject to the SO_RCVLOWAT value of the socket buffer. +subject to the +.Dv SO_RCVLOWAT +value of the socket buffer. +This may be overridden with a per-filter low water mark at the +time the filter is added by setting the +NOTE_LOWAT +flag in +.Va fflags , +and specifying the new low water mark in +.Va data . +On return, .Va data contains the number of bytes in the socket buffer. .Pp If the read direction of the socket has shutdown, then the filter also sets EV_EOF in -.Va flags . +.Va flags , +and returns the socket error (if any) in +.Va fflags . It is possible for EOF to be returned (indicating the connection is gone) while there is still data pending in the socket buffer. .It Vnodes @@ -242,21 +260,33 @@ will contain the amount of space remaining in the write buffer. The filter will set EV_EOF when the reader disconnects, and for the fifo case, this may be cleared by use of EV_CLEAR. Note that this filter is not supported for vnodes. +.Pp +For sockets, the low water mark and socket error handling is +identical to the EVFILT_READ case. .It EVFILT_AIO -A kevent structure is initialized, with -.Va ident -containing the descriptor of the kqueue that the event should be -attached to. The address of the kevent structure is then placed in the -.Va aio_lio_opcode -field of the AIO request, and the aio_* function is then called. -The event will be registered with the specified kqueue, and the +The sigevent portion of the AIO request is filled in, with +.Va sigev_notify_kqueue +containing the descriptor of the kqueue that the event should +be attached to, +.Va sigev_value +containing the udata value, and +.Va sigev_notify +set to SIGEV_EVENT. +When the aio_* function is called, the event will be registered +with the specified kqueue, and the .Va ident argument set to the .Fa struct aiocb returned by the aio_* function. The filter returns under the same conditions as aio_error. .Pp -NOTE: this interface is unstable and subject to change. +Alternatively, a kevent structure may be initialized, with +.Va ident +containing the descriptor of the the kqueue, and the +address of the kevent structure placed in the +.Va aio_lio_opcode +field of the AIO request. However, this approach will not work on +architectures with 64-bit pointers, and should be considered depreciated. .It EVFILT_VNODE Takes a file descriptor as the identifier and the events to watch for in .Va fflags , @@ -276,6 +306,10 @@ The file referenced by the descriptor had its attributes changed. The link count on the file changed. .It NOTE_RENAME The file referenced by the descriptor was renamed. +.It NOTE_REVOKE +Access to the file was revoked via +.Xr revoke 2 +or the underlying fileystem was unmounted. .El .Pp On return, |
