9.1107 unlink

POSIX specification:
http://www.opengroup.org/onlinepubs/9699919799/functions/unlink.html

Gnulib module: unlink

Portability problems fixed by Gnulib:

• Some systems mistakenly succeed on unlink("link-to-file/"): GNU/Hurd, FreeBSD 7.2, AIX 7.1, Solaris 9.
• On Mac OS X 10.10, in a writable HFS mount, unlink("..") succeeds without doing anything.

Portability problems not fixed by Gnulib:

• 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 EPERM. Meanwhile, if a process has the ability to unlink directories, POSIX requires that unlink("symlink-to-dir/") remove dir and leave symlink-to-dir dangling; this behavior is counter-intuitive. The gnulib module unlinkdir can help determine whether code must be cautious of unlinking directories.
• 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.