This vnode call may be used to retrieve a list of named extended attributes
from a specified namespace on a file or directory.
Its arguments are:
The vnode of the file or directory.
Integer constant indicating which extended attribute namespace the attribute
name is present in.
The location of the data to be read.
The resulting data will be a list of attribute names.
Each list entry consists of a single byte containing the length of
the attribute name, followed by the attribute name.
The attribute name is not terminated by
on return it will contain the number of bytes required to read the list.
In most cases
is not, and vice versa.
The user credentials to use in authorizing the request.
The thread requesting the extended attribute.
pointer may be
to indicate that access control checks are not to be performed, if possible.
setting might be used to allow the kernel to authorize extended attribute
retrieval that the active process might not be permitted to do.
Extended attribute semantics may vary by file system implementing the call.
More information on extended attributes may be found in