Description:
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Correct me if I'm wrong, but there doesn't seem to be a single PHP-function that requires backslashes in pathnames on a Windows-box. They all work happily with forward slashes. Personally, I have stopped using backslashes altogether, but there's a single function that's always a thorn in my side: realpath(). That frequently leads to ugly work-arounds such as this:

$path = str_replace('\\', '/', realpath($rawpath));

So I'd like to suggest adding an optional $directorySeparator parameter, that would default to the DIRECTORY_SEPARATOR constant:

$path = realpath($rawpath, '/');

(Actually I'd prefer $directorySeparator to default to '/', but letting it default to DIRECTORY_SEPARATOR will cause no incompatibilities with anyone's existing code...)

Hope that makes sense to you :0)

Reproduce code:
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Expected result:
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Actual result:
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