how to list available drives?

**bleifrei** · 07-22-2006

Hi All!

I found tons of readings/FAQs about how to open, list files, directories, but I was not able to find info about, how the drive listing is working in C. I want to write a file open dialog for a GLUT application, that's why I need to implement drive listing.
I would really appreciate your help if you could show me links, examples, or give advice.

Thx!

**dwks** · 07-22-2006

What OS[es] do you plan for your program to run under?

**bleifrei** · 07-22-2006

I'm writing it under windows, but I'd like to make it as portable as possible.

**cdalten** · 07-22-2006

I don't think it is possible to write a portable program that lists the hard drive. Say you have a hard drive and a cd-rom. On windows, the hard drive might be listed as the c drive and the cd-rom the d drive. On linux, both the hard drive and cd-rom are mounted under a central virtual filesystem. The windows filesystem is decentralized, the linux filesystem is centralized.

**Tonto** · 07-22-2006

Well. I don't really know how it works under linux, but on Windows, you can use the GetLogicalDriveStrings API.

Code:

TCHAR buf[256];
::GetLogicalDriveStrings(sizeof buf, buf);

Then, the buf will contain data like

Code:

"A:\\\0C:\\\0D:\\\0" ...
 'A', ':', '\\', '\0', 'C', ':', '\\', '\0' ...

That being, drive letter, colon, backslash, null byte.

Edit: I guess you could figure out the same information using the http://msdn.microsoft.com/library/de...tdrivetype.asp GetLogicalDrives API.

**xhi** · 07-22-2006

under linux the best way would probably to look in /proc .. and there are several things that would be possibilities.. on mine i have diskstats (which is what df reads from) and then there is also mounts ..

i cant say for sure how uniform everything in /proc will be across distros, but i would think that the two i mentioned should be pretty well the same on anything..

**bleifrei** · 07-23-2006

Thanks for the useful tips guys/girls!

**dwks** · 07-23-2006

Under linux you might be able to use the output of the mount command or /etc/mtab. But Linux doesn't have drive letters.

**xhi** · 07-23-2006

im pretty sure mount reads from /proc/mounts, so it might be easier to just open /proc/mounts..

**dwks** · 07-23-2006

You're right, I think it does.

But anyway, /proc/mounts might look something like this:

Code:

user@0[~]$ cat /proc/mounts
rootfs / rootfs rw 0 0
/dev/root / ext3 rw,noatime 0 0
none /proc proc rw,nodiratime 0 0
none /dev/pts devpts rw 0 0
none /proc/bus/usb usbfs rw 0 0
sysfs /sys sysfs rw 0 0
tmpfs /dev/shm tmpfs rw 0 0
/dev/hdd1 /home ext3 rw,noatime 0 0
user@0[~]$

It gives you the mounted filesystems, but not the drive letters. Your file dialog would have to be different under linux.

**xhi** · 07-23-2006

yeh that would be something to consider, the fact that there is no "C:" in linux. and you wouldnt want to have one in your program, or you would lose credibility pretty fast. (theyre all going to laugh at you

)

the best thing to do would be to list them by the mount points, /, /home, /usr/local etc etc..

/proc/diskstats would be something else to look at.. im not sure what the numbers represent though.. inodes maybe.. they dont correspond to output from `df`.. but im sure you could find the conversion somewhere..

here is what my diskstats reads..

Code:

   3    0 hda 1470003 58786 22797118 4243356 1293616 3150921 35557576 129138256 0 5106396 133381912
   3    1 hda1 371135 3809772 1329141 10633128
   3    2 hda2 0 0 0 0
   3    5 hda5 138694 1422704 348427 2787416
   3    6 hda6 236041 3302410 734559 5876360
   3    7 hda7 576833 5830992 999998 7999984
   3    8 hda8 61620 2486648 118177 945416
   3    9 hda9 144568 5944528 914407 7315256
   3   10 hda10 1 8 2 16
   3   64 hdb 99308 6053900 24612840 624224 0 0 0 0 0 546568 624224
   8    0 sda 458548 398384 6547494 3327688 382776 1707309 16523112 216613044 0 4050900 220214980
   8    1 sda1 0 0 0 0
   8    2 sda2 0 0 0 0
   8    5 sda5 432802 432802 0 0
   8    6 sda6 424153 6114668 2090277 16523112

**dwks** · 07-23-2006

Why don't you give the user the option to type in a directory name. You could chdir() to the directory to see if it's accessable. That way, under linux, you won't have any drive letters, and under windows, the user can just type "E:" if their system has a drive E.

Thread: how to list available drives?

Thread Tools

Search Thread

Display

how to list available drives?

Similar Threads

Anyone good with linked list.....I am not....

List class

Linked list with two class types within template.

singly linked list