aio_mlock(2) asynchronous

LIBRARY

Lb libc

SYNOPSIS

In aio.h Ft int Fn aio_mlock struct aiocb *iocb

DESCRIPTION

The Fn aio_mlock system call allows the calling process to lock into memory the physical pages associated with the virtual address range starting at Fa iocb->aio_buf for Fa 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 Fa iocb pointer may be subsequently used as an argument to Fn aio_return and Fn 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 Fa iocb and the buffer that the Fa 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 Fa iocb should be zeroed before the Fn 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

Rv -std aio_mlock

ERRORS

The Fn aio_mlock system call will fail if:

Bq Er EAGAIN
The request was not queued because of system resource limitations.
Bq Er ENOSYS
The Fn 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 Fn aio_return system call is per the mlock(2) system call, and the value returned by the Fn aio_error system call is one of the error returns from the mlock(2) system call, or Er ECANCELED if the request was explicitly cancelled via a call to Fn aio_cancel .

PORTABILITY

The Fn aio_mlock system call is a Fx extension, and should not be used in portable code.

HISTORY

The Fn aio_mlock system call first appeared in Fx 10.0 .

AUTHORS

The system call was introduced by An Gleb Smirnoff Aq glebius@FreeBSD.org .