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Re: [bulk] - R: /dev/ttys* under cygwin problem


Larry Hall (Cygwin) wrote:
On 9/22/2010 1:29 PM, Daniel Barclay wrote:
Buchbinder, Barry (NIH/NIAID) [E] wrote:
...
To go there directly:
http://www.cygwin.com/cygwin-ug-net/using-specialnames.html#pathnames-posixdevices



Regarding where that page says:


These devices cannot be seen with the command ls /dev/ ...

I've wondered about that--why aren't those special files listed in a
directory listing?

(The Cygwin DLL makes those device files appear when they are referred
to by full pathname; why doesn't it also make them appear in the
containing directory's listing?)

They are implemented in a virtual file system. It is not necessary that there be placeholders in the file system for them to work.

But if they were emulated/simulated _consistently_, one could see which devices were available by simply listing /dev instead of having to re-find the documentation.

Again, why does Cygwin's (virtual) file system _not_ include those
devices (when listing /dev)?  (Why doesn't it do it more like Linux's
/proc, etc., which gives a consistent view and which tells you what's
available without your having to look elsewhere?)


Actually, is your last sentence above actually true? Looking at the device-creation script you pointed me to, I wonder: How do you (e.g., a script) determine which devices of a given type exist (e.g., sda1, sda2, sda3, ...)? (Do you have to try to open each possible device and check whether there's an error?)



But if you
prefer that, you can add them. This is why the documentation has a link
to the script to create the devices in the file system:

<http://cygwin.com/ml/cygwin/2004-03/txt00028.txt>

How do you keep things synchronized? The script you pointed me to appears to be over six years old. I doubt that it matches the code inside Cygwin 1.7.


Daniel




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