freebsd-skq/lib/libc/sys/aio_suspend.2
keramida 9992d6428f ``NULL is a specific instance of a null pointer constant; the generic is
a "null pointer".''

Making good use of the excellent explanations sent to me by Ruslan
Ermilov, Garrett Wollman and Bruce Evans, correct the descriptions of
null pointers.  They are just "null pointers", not nil, not NULL or
".Dv NULL".

Suggested by:	ru, wollman, bde
Reviewed by:	ru, wollman
Pointy hat:	keramida
2004-12-23 23:45:25 +00:00

118 lines
3.2 KiB
Groff

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.\" $FreeBSD$
.\"
.Dd June 2, 1999
.Dt AIO_SUSPEND 2
.Os
.Sh NAME
.Nm aio_suspend
.Nd suspend until asynchronous I/O operations or timeout complete (REALTIME)
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In aio.h
.Ft int
.Fn aio_suspend "const struct aiocb * const iocbs[]" "int niocb" "const struct timespec * timeout"
.Sh DESCRIPTION
The
.Fn aio_suspend
system call suspends the calling process until at least one of the
specified asynchronous I/O requests have completed, a signal is
delivered, or the
.Fa timeout
has passed.
.Pp
The
.Fa iocbs
argument
is an array of
.Fa niocb
pointers to asynchronous I/O requests.
Array members containing
null pointers will be silently ignored.
.Pp
If
.Fa timeout
is not a null pointer, it specifies a maximum interval to suspend.
If
.Fa timeout
is a null pointer, the suspend blocks indefinitely.
To effect a
poll, the
.Fa timeout
should point to a zero-value timespec structure.
.Sh RETURN VALUES
If one or more of the specified asynchronous I/O requests have
completed,
.Fn aio_suspend
returns 0.
Otherwise it returns -1 and sets
.Va errno
to indicate the error, as enumerated below.
.Sh ERRORS
The
.Fn aio_suspend
system call will fail if:
.Bl -tag -width Er
.It Bq Er EAGAIN
the
.Fa timeout
expired before any I/O requests completed.
.It Bq Er EINVAL
The
.Fa iocbs
argument
contains more than
.Dv AIO_LISTIO_MAX
asynchronous I/O requests, or at least one of the requests is not
valid.
.It Bq Er EINTR
the suspend was interrupted by a signal.
.El
.Sh SEE ALSO
.Xr aio_cancel 2 ,
.Xr aio_error 2 ,
.Xr aio_return 2 ,
.Xr aio_waitcomplete 2 ,
.Xr aio_write 2 ,
.Xr aio 4
.Sh STANDARDS
The
.Fn aio_suspend
system call
is expected to conform to the
.St -p1003.1
standard.
.Sh HISTORY
The
.Fn aio_suspend
system call first appeared in
.Fx 3.0 .
.Sh AUTHORS
This
manual page was written by
.An Wes Peters Aq wes@softweyr.com .