How to acess ctime, mtime, … of a symbolic link?

On unix symlinks are pointers to another file. Not only the file but also the symlink has a ctime, mtime, …. I know the symlinks time can be accessed, as ls displays it. If I use one of ruby's File#ctime, File#mtime, …, I always get the attribute of the file the symlink is pointing to, not of the symlink. How can I read this values in ruby? If this is not possible in ruby, tell me how to do it in C. I woul开发者_C百科d write my own c extension in that case.

Use File#lstat(). Example:

# This is a dummy symlink; there's no file named "foo".
ln -s foo bar

# Run irb.
irb(main):001:0> File.lstat("bar")
=> #<File::Stat dev=0x801, ino=90113, mode=0120777, nlink=1, uid=1000, gid=1000, rdev=0x0, size=3, blksize=4096, blocks=0, atime=2010-01-05 17:59:06 -0500, mtime=2010-01-05 17:59:05 -0500, ctime=2010-01-05 17:59:05 -0500>

# Get the mtime of the link.
irb(main):002:0> File.lstat("bar").mtime
=> 2010-01-05 17:59:05 -0500

lstat() can do it in C; not sure if there's a Ruby equivalent.

There're not only the attributes of the symlink and the attributes of the final target, but also, if the symlink is itself to another symlink, one or more intermediate steps; to get all the attributes, you'd need to do lstats in a readlink loop.