Win32 Windows Volume Program and Code Example 8
Getting Logical Drive Program Example
Create a new Win32 console application project and give a suitable project name.
Add the source file and give a suitable name.
Add the following source code.
#include <windows.h>
#include <stdio.h>
// Optional function: Decimal to binary
void decnumtobin(DWORD deci)
{
DWORD input = deci;
DWORD i;
DWORD count = 0;
DWORD binary[128];
do
{
// Modulus 2 to get 1 or a 0
i = input%2;
// Load elements into the binary array
binary[count] = i;
// Divide input by 2 for binary decrement
input = input/2;
// Count the binary digits
count++;
}while (input > 0);
// Reverse and output binary digits
wprintf(LThe bitmask of the logical drives in binary: );
do
{
wprintf(L%d, binary[count - 1]);
count--;
} while (count > 0);
wprintf(L\n);
}
int wmain()
{
// Must give initial value and then let the
// while loop iterates
// There is weird thing here, we need to provide a space
// at the beginning...what wrong here?
WCHAR szDrive[] = L A;
// Get the logical drive mask
DWORD uDriveMask = GetLogicalDrives();
// Display the drive mask
wprintf(LThe bitmask of the logical drives in hex: 0X%.8X\n, uDriveMask);
wprintf(LThe bitmask of the logical drives in decimal: %.8d\n, uDriveMask);
decnumtobin(uDriveMask);
wprintf(LInitial dummy drive string: %s\n, szDrive);
// Verify the returned drive mask
if(uDriveMask == 0)
wprintf(LGetLogicalDrives() failed with error code: %d\n, GetLastError());
else
{
wprintf(LThis machine has the following logical drives:\n);
while(uDriveMask)
{
// use the bitwise AND, 1–available (1 & 1), 0-not available
// the binary representation is in reverse lol
if(uDriveMask & 1)
{
// Just print out the available drives
wprintf(LBitwise AND result = %u, drive %s\n, (uDriveMask & 1), szDrive);
}
// increment for next...
szDrive[1]++;
// shift the bitmask binary right
uDriveMask >>= 1;
}
wprintf(L\n);
}
return 0;
}
Build and run the project. The following screenshot is an output sample.
The following Figure shows the drives when seen in Windows explorer for the previous sample output.
