@node unlink
@section @code{unlink}
@findex unlink

POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/unlink.html}

Gnulib module: unlink

Portability problems fixed by Gnulib:
@itemize
@item
Some systems mistakenly succeed on @code{unlink("link-to-file/")}:
GNU/Hurd, FreeBSD 7.2, AIX 7.1, Solaris 9.
@item
On Mac OS X 10.10, in a writable HFS mount, @code{unlink("..")} succeeds
without doing anything.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@item
Some systems allow a superuser to unlink directories, even though this
can cause file system corruption.  The error given if a process is not
permitted to unlink directories varies across implementations; it is
not always the POSIX value of @code{EPERM}.  Meanwhile, if a process
has the ability to unlink directories, POSIX requires that
@code{unlink("symlink-to-dir/")} remove @file{dir} and leave
@file{symlink-to-dir} dangling; this behavior is counter-intuitive.
The gnulib module unlinkdir can help determine whether code must be
cautious of unlinking directories.
@item
Removing an open file is non-portable: On Unix this allows the programs that
have the file already open to continue working with it; the file's storage
is only freed when the no process has the file open any more.  On Windows,
the attempt to remove an open file fails.
@end itemize