In this Tutorial we are going to go over how to gather & then display all of the drives on your Windows System.

1st, we need to include the Windows.h header, as it is required by the two functions we are going to use from the Widows API.

These functions are GetLogicalDriveStrings & GetDriveType.



These functions are fairly simple to use. In order to get started, we are going to need to declare a buffer. The function GetLogicalDriveStrings simply fills a buffer with Null terminated strings. This is both convenient, & inconvenient. It's convenient, because the strings that it prepares can be fed directly into GetDriveType with no modification. It's inconvenient, because of the Null termination we need to parse it with a pointer.

So getting started, lets create a buffer, & a pointer.



Now we'll fill our buffer, as well as indicate the max size of the buffer. Since we defined MAX to be 256 earlier, we'll just use that


Now dr_avail, defined as char, will contain a Null terminated string of all of our drive letters. Now we'll parse that into the pointer at each Null, & then deal with them individually. Once they are seperated into the Temp pointer, we will pass that pointer to GetDriveType. Since the string already holds the format that GetDriveType requires, we don't need to alter anything. GetDriveType requires the drive letter, the colon, & it must have the backspace. Again, this is exactly how GetLogicalDriveStrings prepares it



Now dr_type holds the int return value from GetDriveType. Lets go over the different return values!



Yup, just the seven different values. Now we just need to increment our pointer & run the loop again.



& that's it! I hope you find this useful. Here is the entire code in one chunk.

#include <stdio.h>
#include <windows.h>

#define MAX 256

int main(void) {
	int dr_type=99;
	char dr_avail[MAX];
	char *temp=dr_avail;
	
	/* 1st we fill the buffer */
	GetLogicalDriveStrings(MAX,dr_avail);
	while(*temp!=NULL) { // Split the buffer by null
		dr_type=GetDriveType(temp);
		switch(dr_type) {
			case 0: // Unknown
			printf("%s : Unknown Drive type\n",temp);
			break;
			case 1: // Invalid
			printf("%s : Drive is invalid\n",temp);
			break;
			case 2: // Removable Drive
			printf("%s : Removable Drive\n",temp);
			break;
			case 3: // Fixed
			printf("%s : Hard Disk (Fixed)\n",temp);
			break;
			case 4: // Remote
			printf("%s : Remote (Network) Drive\n",temp);
			break;
			case 5: // CDROM
			printf("%s : CD-Rom/DVD-Rom\n",temp);
			break;
			case 6: // RamDrive
			printf("%s : Ram Drive\n",temp);
			break;
		}
		temp += lstrlen(temp) +1; // incriment the buffer
	}
	return 0;
}

Well I'm sure it's nice but I can't make it work. I got 3 errors:

1 Error 13 error C2664: 'GetLogicalDriveStringsW' : cannot convert parameter 2 from 'char [256]' to 'LPWSTR'

2 Error 15 error C2664: 'GetDriveTypeW' : cannot convert parameter 1 from 'char *' to 'LPCWSTR'

3 Error 39 error C2664: 'lstrlenW' : cannot convert parameter 1 from 'char *' to 'LPCWSTR'

If you run into these errors, you're configured to use the Unicode character set. This code doesn't take that into account, so you can get it to run by changing to the ANSI multi-byte character set in Project Properties Page->Configuration Properties->General->Project Defaults->Character Set (VS 2008).

I compiled it with command line tools. Know how to use your IDE, is all I can suggest.

Thanks JackOfAllTrades