[Cvs-dev] Re: new dirent module

[Jim Hyslop]

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Derek R. Price wrote:
> Hey Jim,
> 
> Do you know if there is any good reason why I shouldn't rip out most of
> the contrived directory cache in dirent.c and just save hFile in the DIR
> *, then only call _find_first() from opendir(), _find_next() from
> readdir(), and _find_close() from closedir()?

I'm not extremely familiar with the _find functions, but on a quick look
I don't see any problems. The MSDN implies that they are at least
reentrant, if not thread safe: "The _find functions allow nested calls."

> It seems to me that this would save a lot of overhead, so I'm not quite
> sure why it wasn't done this way in the first place.  Are there race
> conditions involved if the directory changes while it is being read by
> the _find* functions?

No more than what would currently happen, as far as I can tell. I just
stepped through the test program provided by the MSDN, which basically
iterates through all *.c files in the current directory and prints out
basic information. After the call to _findnext, I deleted two of the
files, and the program kept going happily. _findfirst appears to take a
snapshot of the directory, just as opendir does.

- --
Jim Hyslop
Dreampossible: Better software. Simply.     http://www.dreampossible.ca
                 Consulting * Mentoring * Training in
    C/C++ * OOD * SW Development & Practices * Version Management
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