NAME¶
aio_mlock
—
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.
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 kernel.
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 indicate
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⟩.