Unicode question
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From: Jack on 15 Dec 2009 07:25 Hi vc gurus, bool LoadMesh(std::wstring szPath) { //... ::GetModuleFileNameW(NULL, (LPWCH) szPath.c_str(), szPath.size()); szPath.append(szfilename); //// Open .dat mesh HANDLE h = CreateFileW((LPCWSTR)szPath.c_str(), GENERIC_READ, NULL, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL); if (h == INVALID_HANDLE_VALUE) { MessageBoxA(NULL, "Couldn't open file with CreateFile()", "Error", MB_OK); return E_FAIL; } //..... The handle "h" is always 0xffffffff, does anyone know which part is wrong? Thanks Jack
From: Jack on 15 Dec 2009 07:27 > > bool LoadMesh(std::wstring szPath) bool LoadMesh(std::wstring szFilename) { Thanks Jack
From: Jack on 15 Dec 2009 07:32 A side note: When I use ASCII, hence CreateFileA, it loads the mesh correctly (h is valid)... Thanks Jack
From: Giovanni Dicanio on 15 Dec 2009 07:38 "Jack" <jl(a)knight.com> ha scritto nel messaggio news:O7ncwGYfKHA.2780(a)TK2MSFTNGP05.phx.gbl... > bool LoadMesh(std::wstring szPath) I would pass an input string using a const reference, to avoid deep-copies, e.g. bool LoadMesh( const std::wstring & path ) Moreover, I tend to prefer CString class instead of STL [w]string for Win32 coding. > ::GetModuleFileNameW(NULL, (LPWCH) szPath.c_str(), szPath.size()); I don't think that you can modify the content of an STL string using c_str (this method returns a const pointer to enforce that). Moreover, I don't like explicitly specifying the 'W' suffix for Win32 APIs (compiling in Unicode is just fine). I would write some code like this: CString strFilename; static const int cchFilename = 4096; TCHAR * pszFilename = strFilename.GetBuffer( cchFilename ); ::GetModuleFileName( NULL, pszFilename, cchFilename ); ... verify return code... strFilename.ReleaseBuffer(); Now 'strFilename' should contain the required string. > //// Open .dat mesh > HANDLE h = CreateFileW((LPCWSTR)szPath.c_str(), I would just use CreateFile (not CreateFileW) in Unicode builds. If szPath is an instance of std::wstring, you don't need an LPCWSTR cast for the return value of c_str(), it is already a 'const wchar_t *', i.e. LPCWSTR. Giovanni
From: Giovanni Dicanio on 15 Dec 2009 11:24
"Jack" <jl(a)knight.com> ha scritto nel messaggio news:O7ncwGYfKHA.2780(a)TK2MSFTNGP05.phx.gbl... > bool LoadMesh(std::wstring szPath) [...] > //// Open .dat mesh > HANDLE h = CreateFileW((LPCWSTR)szPath.c_str(), GENERIC_READ, NULL, NULL, > OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL); > if (h == INVALID_HANDLE_VALUE) > { > MessageBoxA(NULL, "Couldn't open file with CreateFile()", "Error", > MB_OK); > return E_FAIL; > } I was missing that (not directly related to your original problem, but probably worth mentioning): 1. Your function's return value is 'bool'. So you should return something like 'true' or 'false', but not E_FAIL. You should use E_FAIL if your function returns an HRESULT. 2. Instead of using MessageBoxA, you may want to use MessageBox, and decorate your string literals using _T() (which will work in both ANSI/MBCS and Unicode builds) or L"..." (Unicode builds only), e.g.: MessageBox( NULL, L"Couldn't open file with CreateFile()", L"Error", MB_OK ); A better approach would be to store strings in resources (instead of using string literals in source code), and load these messages from resources. > The handle "h" is always 0xffffffff, does anyone know which part is wrong? Please verify the content of 'szPath' passed to CreateFileW. HTH, Giovanni |