Listing the files in a directory

The following example calls FindFirstFile, FindNextFile, and FindClose to list files in a specified directory.

#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);
}