diff options
Diffstat (limited to 'lib/libc')
| -rw-r--r-- | lib/libc/sys/kqueue.2 | 40 |
1 files changed, 32 insertions, 8 deletions
diff --git a/lib/libc/sys/kqueue.2 b/lib/libc/sys/kqueue.2 index 5cc1ef804cd1..0ea64bbe0801 100644 --- a/lib/libc/sys/kqueue.2 +++ b/lib/libc/sys/kqueue.2 @@ -34,12 +34,12 @@ .Sh LIBRARY .Lb libc .Sh SYNOPSIS +.Fd #include <sys/types.h> .Fd #include <sys/event.h> .Ft int .Fn kqueue "void" .Ft int -.Fn kevent "int kq" "int nchanges" "struct kevent **changelist" \ -"int nevents" "struct kevent *eventlist" "struct timespec *timeout" +.Fn kevent "int kq" "int nchanges" "struct kevent **changelist" "int nevents" "struct kevent *eventlist" "struct timespec *timeout" .Sh DESCRIPTION .Fn kqueue provides a generic method of notifying the user when an event @@ -68,6 +68,10 @@ on a file descriptor will remove any kevents that reference the descriptor. .Pp .Fn kqueue creates a new kernel event queue and returns a descriptor. +The queue is not inherited by a child created with +.Xr fork 2 . +However, you can perform a rfork() and share the descriptor table, +which will allow sharing of the kqueue between two processes. .Pp .Fn kevent is used to register events with the queue, and return any pending @@ -331,17 +335,22 @@ returns the number of times the signal has occurred since the last call to This filter automatically sets the EV_CLEAR flag internally. .El .Sh RETURN VALUES +.Fn kqueue +creates a new kernel event queue and returns a file descriptor. +If there was an error creating the kernel event queue, a value of -1 is +returned and errno set. +.Pp .Fn kevent returns the number of events placed in the -.Ar eventlist , +.Fa eventlist , up to the value given by -.Ar nevents . +.Fa nevents . If an error occurs while processing an element of the -.Ar changelist +.Fa changelist and there is enough room in the -.Ar eventlist , +.Fa eventlist , then the event will be placed in the -.Ar eventlist +.Fa eventlist with .Dv EV_ERROR set in @@ -358,6 +367,18 @@ If the time limit expires, then returns 0. .Sh ERRORS The +.Fn kqueue +function fails if: +.Bl -tag -width Er +.It Bq Er ENOMEM +The kernel failed to allocate enough memory for the kernel queue. +.It Bq Er EMFILE +The per-process descriptor table is full. +.It Bq Er ENFILE +The system file table is full. +.El +.Pp +The .Fn kevent function fails if: .Bl -tag -width Er @@ -395,9 +416,12 @@ The and .Fn kevent functions first appeared in -.Fx 5.0 . +.Fx 4.1 . .Sh AUTHORS The .Fn kqueue system and this manual page were written by .An Jonathan Lemon Aq jlemon@FreeBSD.org . +.Sh BUGS +It is currently not possible to watch a vnode that resides on anything but +a UFS file system. |