Obtaining a File Name From a File Handle
The following example obtains a file name from a handle to a file object using a file mapping object. It uses the CreateFileMapping and MapViewOfFile functions to create the mapping. Next, it uses the GetMappedFileName function to obtain the file name. For remote files, it prints the device path received from this function. For local files, it converts the path to use a drive letter and prints this path. To test this code, create a main function that opens a file using CreateFile and passes the resulting handle to GetFileNameFromHandle.
#include <windows.h> #include <stdio.h> #include <tchar.h> #include <string.h> #include <psapi.h> #include <strsafe.h> #define BUFSIZE 512 BOOL GetFileNameFromHandle(HANDLE hFile) { BOOL bSuccess = FALSE; TCHAR pszFilename[MAX_PATH+1]; HANDLE hFileMap; // Get the file size. DWORD dwFileSizeHi = 0; DWORD dwFileSizeLo = GetFileSize(hFile, &dwFileSizeHi); if( dwFileSizeLo == 0 && dwFileSizeHi == 0 ) { _tprintf(TEXT("Cannot map a file with a length of zero.\n")); return FALSE; } // Create a file mapping object. hFileMap = CreateFileMapping(hFile, NULL, PAGE_READONLY, 0, 1, NULL); if (hFileMap) { // Create a file mapping to get the file name. void* pMem = MapViewOfFile(hFileMap, FILE_MAP_READ, 0, 0, 1); if (pMem) { if (GetMappedFileName (GetCurrentProcess(), pMem, pszFilename, MAX_PATH)) { // Translate path with device name to drive letters. TCHAR szTemp[BUFSIZE]; szTemp[0] = '\0'; if (GetLogicalDriveStrings(BUFSIZE-1, szTemp)) { TCHAR szName[MAX_PATH]; TCHAR szDrive[3] = TEXT(" :"); BOOL bFound = FALSE; TCHAR* p = szTemp; do { // Copy the drive letter to the template string *szDrive = *p; // Look up each device name if (QueryDosDevice(szDrive, szName, MAX_PATH)) { size_t uNameLen = _tcslen(szName); if (uNameLen < MAX_PATH) { bFound = _tcsnicmp(pszFilename, szName, uNameLen) == 0 && *(pszFilename + uNameLen) == _T('\\'); if (bFound) { // Reconstruct pszFilename using szTempFile // Replace device path with DOS path TCHAR szTempFile[MAX_PATH]; StringCchPrintf(szTempFile, MAX_PATH, TEXT("%s%s"), szDrive, pszFilename+uNameLen); StringCchCopyN(pszFilename, MAX_PATH+1, szTempFile, _tcslen(szTempFile)); } } } // Go to the next NULL character. while (*p++); } while (!bFound && *p); // end of string } } bSuccess = TRUE; UnmapViewOfFile(pMem); } CloseHandle(hFileMap); } _tprintf(TEXT("File name is %s\n"), pszFilename); return(bSuccess); } int _tmain(int argc, TCHAR *argv[]) { HANDLE hFile; if( argc != 2 ) { _tprintf(TEXT("This sample takes a file name as a parameter.\n")); return 0; } hFile = CreateFile(argv[1], GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL); if(hFile == INVALID_HANDLE_VALUE) { _tprintf(TEXT("CreateFile failed with %d\n"), GetLastError()); return 0; } GetFileNameFromHandle( hFile ); }
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Build date: 2/7/2012
GetFinalPathNameByHandle
Vista+ or Server 2008+ applications can call GetFinalPathNameByHandle() instead.
- 4/7/2008
- Josh Poley [MSFT]