The predefined PHP constant DIRECTORY_SEPARATOR is useless.
When evaluated, the constant is as follows: *nix: / win: \
So, to the casual observer, there seems to be a real need for this constant – especially with those who favor the php command getcwd(). However, for the most part, it is just wasteful – and potentially error prone to have around.
For the slashes, Windows will work with / (even though its constant return is \ – and the backslash is used normally throughout the filesystem). Windows will also work with c:\blah\blah/additionalblah/moreblah.php (note the mixed slashes, just in case you happen to mix a call to something like getcwd() and your hardset path with the forward slash). *nix will not (you cannot do /usr\bin/funstuff)
I also ran across a case one time where – through some strange fate of mangled programming, the DIRECTORY_SEPARATOR on windows encased in a string started escaping certain characters of the filename.
One final note – someone on the PHP.net manual page suggested this function – if you really MUST use getcwd() – and in the case you’re using ‘explode()’ to figure out something about the path:
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I was going to disagree, but I can’t. Its useless. Except one minor thing. Since Unix file systems allow \ in a file name (its not smart to do, but possible), the above gstr_replace wouldn’t work in that one case. But oh well. Its not worth it to support that one case.