How to get the list of all drives in C - c

Question

Is there any method using which i can list down all the available drives and their folder content. ie i want to access all the drives and then the folders in each drive and then the sub-folders of each folder and so on till the last possible level in each drive.
C language .. Windows platform .. i have tried using alphabetic array with system() but am unable to get the names of files and folders .

Answer 1

This is not "standard C" (ie: ANSI, C89, C99, etc), but it makes minimal use of operating-system specific calls (ie: just "windows.h", not MS .NET or MFC technologies). This is the minimalist approach to what you are attempting to do. Once you have a list of all drive letters, you need to query each drive recursively for its directory listings.
This is a mix of C and C++, but you'll likely be using a free version of Visual Studio to build this anyways.
Code Listing - Get drive letters
#include <windows.h>
#include <stdio.h>
int main()
{
char buf[255];
// get the drive letters as a set of strings
int sz = GetLogicalDriveStrings(sizeof(buf), buf);
if( sz > 0)
{
// buf now contains a list of all the drive letters. Each drive letter is
// terminated with '\0' and the last one is terminated by two consecutive '\0' bytes.
char* p1 = buf;
char* p2;
while( *p1 != '\0' && (p2 = strchr(p1,'\0')) != NULL )
{
printf("%s\n", p1);
p1 = p2+1;
}
}
else
{
// Oops! something went wrong so display the error message
DWORD dwError = GetLastError();
FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, 0, dwError, 0, buf, sizeof(buf), 0);
printf("%s\n", buf);
}
}
Code Listing - Directory listing
#include <windows.h>
#include <tchar.h>
#include <stdio.h>
#include <strsafe.h>
#pragma comment(lib, "User32.lib")
void DisplayErrorBox(LPTSTR lpszFunction);
int _tmain(int argc, TCHAR *argv[])
{
WIN32_FIND_DATA ffd;
LARGE_INTEGER filesize;
TCHAR szDir[MAX_PATH];
size_t length_of_arg;
HANDLE hFind = INVALID_HANDLE_VALUE;
DWORD dwError=0;
// If the directory is not specified as a command-line argument,
// print usage.
if(argc != 2)
{
_tprintf(TEXT("\nUsage: %s <directory name>\n"), argv[0]);
return (-1);
}
// Check that the input path plus 3 is not longer than MAX_PATH.
// Three characters are for the "\*" plus NULL appended below.
StringCchLength(argv[1], MAX_PATH, &length_of_arg);
if (length_of_arg > (MAX_PATH - 3))
{
_tprintf(TEXT("\nDirectory path is too long.\n"));
return (-1);
}
_tprintf(TEXT("\nTarget directory is %s\n\n"), argv[1]);
// Prepare string for use with FindFile functions. First, copy the
// string to a buffer, then append '\*' to the directory name.
StringCchCopy(szDir, MAX_PATH, argv[1]);
StringCchCat(szDir, MAX_PATH, TEXT("\\*"));
// Find the first file in the directory.
hFind = FindFirstFile(szDir, &ffd);
if (INVALID_HANDLE_VALUE == hFind)
{
DisplayErrorBox(TEXT("FindFirstFile"));
return dwError;
}
// List all the files in the directory with some info about them.
do
{
if (ffd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
{
_tprintf(TEXT(" %s <DIR>\n"), ffd.cFileName);
}
else
{
filesize.LowPart = ffd.nFileSizeLow;
filesize.HighPart = ffd.nFileSizeHigh;
_tprintf(TEXT(" %s %ld bytes\n"), ffd.cFileName, filesize.QuadPart);
}
}
while (FindNextFile(hFind, &ffd) != 0);
dwError = GetLastError();
if (dwError != ERROR_NO_MORE_FILES)
{
DisplayErrorBox(TEXT("FindFirstFile"));
}
FindClose(hFind);
return dwError;
}
void DisplayErrorBox(LPTSTR lpszFunction)
{
// Retrieve the system error message for the last-error code
LPVOID lpMsgBuf;
LPVOID lpDisplayBuf;
DWORD dw = GetLastError();
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
dw,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &lpMsgBuf,
0, NULL );
// Display the error message and clean up
lpDisplayBuf = (LPVOID)LocalAlloc(LMEM_ZEROINIT,
(lstrlen((LPCTSTR)lpMsgBuf)+lstrlen((LPCTSTR)lpszFunction)+40)*sizeof(TCHAR));
StringCchPrintf((LPTSTR)lpDisplayBuf,
LocalSize(lpDisplayBuf) / sizeof(TCHAR),
TEXT("%s failed with error %d: %s"),
lpszFunction, dw, lpMsgBuf);
MessageBox(NULL, (LPCTSTR)lpDisplayBuf, TEXT("Error"), MB_OK);
LocalFree(lpMsgBuf);
LocalFree(lpDisplayBuf);
}
References
List Windows Logical Drive Letters, Accessed 2014-08-01, <http://www.daniweb.com/software-development/c/code/237803/list-windows-logical-drive-letters>
Listing the Files in a Directory, Accessed 2014-08-01, <http://msdn.microsoft.com/en-us/library/windows/desktop/aa365200%28v=vs.85%29.aspx>

Answer 2

Standard C has no way to directly address the drive, or, for that matter, even know what a drive is.
Generally, each C compiler vendor will include a library which handles those things for the specific platform the compiler is written for. But these are all specific to the vendor.
Boost has cross-platform library for C++, including one for dealing with the file system.