Can Tcl determine between a CDROM and Hardrive?

[hija]

I am trying to create a procedure that searches the PC to find out what Drives [logical] exist on a system.
This is in a windows environment.
The reason is to be able to search for a specific directory that should exist on the PC.

So using :
set volumes [file volume]
regsub {\s} $volumes {} drives
set drive [split drives /]

gets me the drive list, then using a foreach loop I can use
cd $drive
and then

if {[file exists "FindDirectory"] == 1 }{
'do something in that directory'
}

This works fine until I reach a CDROM drive at which point Tcl says it cannot change directory to this drive and so grinds to a halt..

Is there some way I can get Tcl to skip over the CDROM by recognising it is not a writable device or some other parameter that can be used so the loop can be caused to skip over it using 'continue'

 

[marsd]

Why don't you use file writable?
if {[file exists $filename] && [file writable $filename]} {
do something..
}

 

[hija]

marsd,
thanks marsd this works fine in fact I did not need the 'file exists' bit I just need to be able to make the proc skip over looking at the cdrom, as the directory in question will always reside on a hardrive but i could not guaruntee that it will always be on the HOME or SystemDrive hence the need to search all volumes that might exist.

hija