1.\" Copyright (c) 2013 Gleb Smirnoff <glebius@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd June 3, 2013 28.Dt AIO_MLOCK 2 29.Os 30.Sh NAME 31.Nm aio_mlock 32.Nd asynchronous 33.Xr mlock 2 34operation 35.Sh LIBRARY 36.Lb libc 37.Sh SYNOPSIS 38.In aio.h 39.Ft int 40.Fn aio_mlock "struct aiocb *iocb" 41.Sh DESCRIPTION 42The 43.Fn aio_mlock 44system call allows the calling process to lock into memory the 45physical pages associated with the virtual address range starting at 46.Fa iocb->aio_buf 47for 48.Fa iocb->aio_nbytes 49bytes. 50The call returns immediately after the locking request has 51been enqueued; the operation may or may not have completed at the time 52the call returns. 53.Pp 54The 55.Fa iocb 56pointer may be subsequently used as an argument to 57.Fn aio_return 58and 59.Fn aio_error 60in order to determine return or error status for the enqueued operation 61while it is in progress. 62.Pp 63If the request could not be enqueued (generally due to 64.Xr aio 4 65limits), 66then the call returns without having enqueued the request. 67.Sh RESTRICTIONS 68The Asynchronous I/O Control Block structure pointed to by 69.Fa iocb 70and the buffer that the 71.Fa iocb->aio_buf 72member of that structure references must remain valid until the 73operation has completed. 74For this reason, use of auto (stack) variables 75for these objects is discouraged. 76.Pp 77The asynchronous I/O control buffer 78.Fa iocb 79should be zeroed before the 80.Fn aio_mlock 81call to avoid passing bogus context information to the kernel. 82.Pp 83Modifications of the Asynchronous I/O Control Block structure or the 84buffer contents after the request has been enqueued, but before the 85request has completed, are not allowed. 86.Sh RETURN VALUES 87.Rv -std aio_mlock 88.Sh ERRORS 89The 90.Fn aio_mlock 91system call will fail if: 92.Bl -tag -width Er 93.It Bq Er EAGAIN 94The request was not queued because of system resource limitations. 95.It Bq Er ENOSYS 96The 97.Fn aio_mlock 98system call is not supported. 99.El 100.Pp 101If the request is successfully enqueued, but subsequently cancelled 102or an error occurs, the value returned by the 103.Fn aio_return 104system call is per the 105.Xr mlock 2 106system call, and the value returned by the 107.Fn aio_error 108system call is one of the error returns from the 109.Xr mlock 2 110system call, or 111.Er ECANCELED 112if the request was explicitly cancelled via a call to 113.Fn aio_cancel . 114.Sh SEE ALSO 115.Xr aio_cancel 2 , 116.Xr aio_error 2 , 117.Xr aio_return 2 , 118.Xr mlock 2 , 119.Xr aio 4 120.Sh PORTABILITY 121The 122.Fn aio_mlock 123system call is a 124.Fx 125extension, and should not be used in portable code. 126.Sh HISTORY 127The 128.Fn aio_mlock 129system call first appeared in 130.Fx 10.0 . 131.Sh AUTHORS 132The system call was introduced by 133.An Gleb Smirnoff Aq glebius@FreeBSD.org . 134