AIO_MLOCK(2)              FreeBSD System Calls Manual             AIO_MLOCK(2)

NAME
     aio_mlock - asynchronous mlock(2) operation

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <aio.h>

     int
     aio_mlock(struct aiocb *iocb);

DESCRIPTION
     The aio_mlock() system call allows the calling process to lock into
     memory the physical pages associated with the virtual address range
     starting at iocb->aio_buf for iocb->aio_nbytes bytes.  The call returns
     immediately after the locking request has been enqueued; the operation
     may or may not have completed at the time the call returns.

     The iocb pointer may be subsequently used as an argument to aio_return()
     and aio_error() in order to determine return or error status for the
     enqueued operation while it is in progress.

     If the request could not be enqueued (generally due to aio(4) limits),
     then the call returns without having enqueued the request.

     The iocb->aio_sigevent structure can be used to request notification of
     the operation's completion as described in aio(4).

RESTRICTIONS
     The Asynchronous I/O Control Block structure pointed to by iocb and the
     buffer that the iocb->aio_buf member of that structure references must
     remain valid until the operation has completed.

     The asynchronous I/O control buffer iocb should be zeroed before the
     aio_mlock() call to avoid passing bogus context information to the
     kernel.

     Modifications of the Asynchronous I/O Control Block structure or the
     memory mapping described by the virtual address range are not allowed
     while the request is queued.

RETURN VALUES
     The aio_mlock() function returns the value 0 if successful; otherwise the
     value -1 is returned and the global variable errno is set to indicate the
     error.

ERRORS
     The aio_mlock() system call will fail if:

     [EAGAIN]           The request was not queued because of system resource
                        limitations.

     [EINVAL]           The asynchronous notification method in
                        iocb->aio_sigevent.sigev_notify is invalid or not
                        supported.

     If the request is successfully enqueued, but subsequently cancelled or an
     error occurs, the value returned by the aio_return() system call is per
     the mlock(2) system call, and the value returned by the aio_error()
     system call is one of the error returns from the mlock(2) system call, or
     ECANCELED if the request was explicitly cancelled via a call to
     aio_cancel().

SEE ALSO
     aio_cancel(2), aio_error(2), aio_return(2), mlock(2), sigevent(3), aio(4)

PORTABILITY
     The aio_mlock() system call is a FreeBSD extension, and should not be
     used in portable code.

HISTORY
     The aio_mlock() system call first appeared in FreeBSD 10.0.

AUTHORS
     The system call was introduced by Gleb Smirnoff <glebius@FreeBSD.org>.

FreeBSD 13.1-RELEASE-p6         August 19, 2016        FreeBSD 13.1-RELEASE-p6