function removes the link named by
from its directory and decrements the link count of the
file which was referenced by the link.
If that decrement reduces the link count of the file
and no process has the file open, then
all resources associated with the file are reclaimed.
If one or more processes have the file open when the last link is removed,
the link is removed, but the removal of the file is delayed until
all references to it have been closed.
Upon successful completion, a value of 0 is returned.
Otherwise, a value of \-1 is returned and
is set to indicate the error.
A component of the path prefix is not a directory.
A component of a pathname exceeded
characters, or an entire path name exceeded
The named file does not exist.
Search permission is denied for a component of the path prefix.
Write permission is denied on the directory containing the link
to be removed.
Too many symbolic links were encountered in translating the pathname.
The named file is a directory and the effective user ID
of the process is not the superuser, or the file system
containing the file does not permit the use of
on a directory.
The directory containing the file is marked sticky,
and neither the containing directory nor the file to be removed
are owned by the effective user ID.
The named file has its immutable or append-only flag set (see
The entry to be unlinked is the mount point for a
mounted file system.
An I/O error occurred while deleting the directory entry
or deallocating the inode.
The named file resides on a read-only file system.
points outside the process's allocated address space.