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view doc/posix-functions/readlinkat.texi @ 40139:3bacbf659cc9
ttyname_r: Work around bug on Android 4.3.
* m4/ttyname_r.m4 (gl_FUNC_TTYNAME_R): Test whether ttyname_r is a stub.
* lib/ttyname_r.c (ttyname_r): Implement for Android.
* doc/posix-functions/ttyname_r.texi: Mention the Android bug.
* doc/posix-functions/ttyname.texi: Likewise.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Sat, 26 Jan 2019 11:56:31 +0100 |
parents | 65bc0f9b42bf |
children |
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@node readlinkat @section @code{readlinkat} @findex readlinkat POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/readlinkat.html} Gnulib module: readlinkat Portability problems fixed by Gnulib: @itemize @item This function is missing on some platforms: glibc 2.3.6, Mac OS X < 10.10, 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 14, Interix 3.5, BeOS, Android 4.4. But the replacement function is not safe to be used in libraries and is not multithread-safe. @item Some platforms mistakenly succeed on @code{readlink("link/",buf,len)}: Mac OS X 10.10. @item On some platforms, @code{readlinkat} returns @code{int} instead of @code{ssize_t}: AIX 7.1. @item @end itemize Portability problems not fixed by Gnulib: @itemize @item This function always fails on platforms that don't support symlinks: mingw, MSVC 14. @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 @code{areadlink} for improved ability to read symlink contents. @end itemize