2 @section @code{readlinkat}
5 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/readlinkat.html}
7 Gnulib module: readlinkat
9 Portability problems fixed by Gnulib:
12 This function is missing on some platforms:
13 glibc 2.3.6, Mac OS X < 10.10, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8,
14 AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw, MSVC 9, Interix 3.5, BeOS.
15 But the replacement function is not safe to be used in libraries and is not multithread-safe.
17 Some platforms mistakenly succeed on @code{readlink("link/",buf,len)}:
20 On some platforms, @code{readlinkat} returns @code{int} instead of
26 Portability problems not fixed by Gnulib:
29 This function always fails on platforms that don't support symlinks:
32 When @code{readlink} is called on a directory: In the case of NFS mounted
33 directories, Cygwin sets @code{errno} to @code{ENOENT} or @code{EIO} instead of
34 @code{EINVAL}. To avoid this problem, check for a directory before calling
37 When @code{readlink} is called on a file that is not a symbolic link:
38 Irix may set @code{errno} to @code{ENXIO} instead of @code{EINVAL}. Cygwin
39 may set errno to @code{EACCES} instead of @code{EINVAL}.
41 Symlink contents do not always have a trailing null byte, and there is
42 no indication if symlink contents were truncated if the return value
43 matches the length. Furthermore, AIX 5.1 and HP-UX 11 set
44 @code{errno} to @code{ERANGE} rather than returning truncated
45 contents, and Linux sets @code{errno} to @code{EINVAL} if the
46 requested length is zero. Use the gnulib module areadlink for
47 improved ability to read symlink contents.