Merge tag 'snapshot-start' into stable

[gnulib.git] / doc / posix-functions / readlinkat.texi

diff --git a/doc/posix-functions/readlinkat.texi b/doc/posix-functions/readlinkat.texi
index 11bf5e2..a2988f2 100644 (file)
--- a/doc/posix-functions/readlinkat.texi
+++ b/doc/posix-functions/readlinkat.texi
@@ -2,17 +2,39 @@
 @section @code{readlinkat}
 @findex readlinkat
 
-POSIX specification: @url{http://www.opengroup.org/onlinepubs/9699919799/functions/readlinkat.html}
+POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/readlinkat.html}
 
-Gnulib module: ---
+Gnulib module: readlinkat
 
 Portability problems fixed by Gnulib:
 @itemize
+@item
+This function is missing on some platforms:
+glibc 2.3.6, Mac OS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8,
+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.
+But the replacement function is not safe to be used in libraries and is not multithread-safe.
 @end itemize
 
 Portability problems not fixed by Gnulib:
 @itemize
 @item
-This function is missing on some platforms:
-glibc 2.3.6, MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin, mingw, Interix 3.5, BeOS.
+This function always fails on platforms that don't support symlinks:
+mingw, MSVC 9.
+@item
+When @code{readlink} is called on a directory: In the case of NFS mounted
+directories, Cygwin sets @code{errno} to @code{ENOENT} or @code{EIO} instead of
+@code{EINVAL}.  To avoid this problem, check for a directory before calling
+@code{readlink}.
+@item
+When @code{readlink} is called on a file that is not a symbolic link:
+Irix may set @code{errno} to @code{ENXIO} instead of @code{EINVAL}.  Cygwin
+may set errno to @code{EACCES} instead of @code{EINVAL}.
+@item
+Symlink contents do not always have a trailing null byte, and there is
+no indication if symlink contents were truncated if the return value
+matches the length.  Furthermore, AIX 5.1 and HP-UX 11 set
+@code{errno} to @code{ERANGE} rather than returning truncated
+contents, and Linux sets @code{errno} to @code{EINVAL} if the
+requested length is zero.  Use the gnulib module areadlink for
+improved ability to read symlink contents.
 @end itemize