fd_advise()
Advise the system about how a file will be used.
Description
The fd_advise()
function is used to provide advice to the operating system about the intended usage of a file. This advice can help the system optimize performance or memory usage based on the specified parameters.
Syntax
;;; Note: This is similar to `posix_fadvise` in POSIX.
;;; Provide file advisory information on a file descriptor.
(@interface func (export "fd_advise")
(param $fd $fd)
;;; The offset within the file to which the advisory applies.
(param $offset $filesize)
;;; The length of the region to which the advisory applies.
(param $len $filesize)
;;; The advice.
(param $advice $advice)
(result $error (expected (error $errno)))
)
Parameters
ctx
: A mutable reference to the function environment.fd
: The file descriptor to which the advice applies.offset
: The offset from which the advice applies.len
: The length from the offset to which the advice applies.advice
: The advice to be given to the operating system.
Return Value
The function returns an Errno
value indicating the success or failure of the operation.
Note
The fd_advise()
function allows applications to inform the operating system about the expected usage patterns of a file. The actual impact of the advice depends on the underlying operating system and filesystem implementation.
The implementation of this function currently returns Errno::Success
to indicate a valid implementation, although the advice may not be actively utilized.
Logging
This function has been instrumented with debug-level logging. It will log the following information:
fd
: The file descriptor provided.offset
: The offset from which the advice applies.len
: The length from the offset to which the advice applies.advice
: The advice given.