Cocoa: detect unmountable volume

Question

I folks,

I am developing a small app which should be able to unmount volumes.

Currently, I am using the following code to determine whether a volume is unmountable or not:

BOOL isRemovable, isWritable, isUnmountable;
NSString *description, *type;

BOOL succ = [ws getFileSystemInfoForPath:[itemInfo objectForKey:@"path"]
                isRemovable:&isRemovable
                isWritable:&isWritable
                isUnmountable:&isUnmountable
                description:&description
                type:&type];

The problem is that only physically removable volumes like a CD or DVD get isUnmountable=YES flag. USB devices don't, although these are unmountable, too.

Do you guys have a solution for that?

---- Edit

I tried it out with another USB stick which is FAT formatted. I got 2 USB hard disks connected to my mac which are unmountable via the Finder or Disk Utility - these are HFS formatted. I created an output which uses the code from above:

/, hfs, unmountable: NO, removable: NO
/Volumes/Elephant, hfs, unmountable: NO, removable: NO
/Volumes/Time Machine, hfs, unmountable: NO, removable: NO
/Volumes/USBSTICK, msdos, unmountable: YES, removable: YES

It looks like the method only returns YES if the device is FAT or MSDOS formatted. This is weird because the other 2 (Elephant, Time Machine) are volumes that are connected via USB and have to be removable and unmountable. Is there another way to get that information or have I done something wrong in my code?

--

Regards

Marco

Answer 1

Using your exact code, with my own USB stick (a 1GB Cruzer - yes, I know I'm behind), I'm getting a YES for isRemovable.

Though BOOL is usually represented as YES or NO, TRUE works. To make sure, I tested that as well. I'm getting isRemovable == TRUE/YES every time.

So since the condition "can be unmounted/removed" can depend on whether something is actually using a resource on the volume, it's likely that's what's preventing this method from answering with a "go ahead and unmount it." More context in your question might help identify that something.