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From: Beman Dawes (bdawes_at_[hidden])
Date: 2004-12-13 16:19:57

At 04:42 PM 12/12/2004, Ben Hutchings wrote:

>I noticed that Boost.Filesystem doesn't use readdir_r to iterate over
>directories, even if it is available, making that non-thread-safe.
>There is a comment to this effect in operations_posix_windows.cpp.
>I've attached a patch that I believe will allow it to detect whether
>readdir_r is available and to use it iff it is. I have only tested this
>on Linux with g++ 3.3, but I tried deliberately breaking the declaration
>of readdir_r and verified that the code continues to work without it.

Interesting approach!

I guess the alternative is hand configuration, and that isn't very
attractive. So let me take a look at your patch in detail and get back to

>On a visual inspection some time back I also noted that there's no
>special handling for empty root directories on Windows. The problem
>with these is that while even an empty directory normally has entries
>for "." and "..", so that FindFirstFile can return something, root
>directories on FAT volumes (and I think NTFS as well) do not have these
>and Windows doesn't fake them, so FindFirstFile on an empty root returns
>INVALID_HANDLE_VALUE. Note that this only applies to real root
>directories, not to the roots of drives that are mapped to
>sub-directories using subst or file sharing. I never got round to
>checking whether the Boost code actually handles this or not, as I only
>use Windows at work and we don't use Boost.Filesystem there. Perhaps
>someone could check that out?

I've got some code that should serve to check that out. I'll let you know.

> Unfortunately it's impractical to test
>automatically, as empty volumes are hard to generate on demand!

That's one of the difficulties of the library; there are quite a few test
cases which are difficult and/or expensive to create on demand for testing.

Thanks for you help,


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