freebsd man page for aio_mlock

AIO_MLOCK(2)						      BSD 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 opera-
     tion 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.

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.  For this reason, use of auto (stack) variables for these objects is discouraged.

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

     Modifications of the Asynchronous I/O Control Block structure or the buffer contents after the request has been enqueued, but before the
     request has completed, are not allowed.

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 indi-
     cate the error.

ERRORS
     The aio_mlock() system call will fail if:

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

     [ENOSYS]		The aio_mlock() system call is 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), 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>.

BSD
								   June 3, 2013 							       BSD