sscanf_s cannot convert ...from 'WCHAR[260] to 'const char *' error.

[Akino877]

Hello,

I have a small program which uses FindFirstFile() to get a file name. Once I get the file name, I would like to use sscanf to extract certain part of the file name.

My program is as follows :

......
int _tmain(int argc, _TCHAR* argv[])
{
WIN32_FIND_DATA ffd;
TCHAR szDir[MAX_PATH];
HANDLE hFind = INVALID_HANDLE_ VALUE;
DWORD dwError = 0;
char filename[128];
char ext[128];

StringCchCopy (szDir, MAX_PATH, TEXT(".\\*.dat" ));
hFind = FindFirstFile (szDir, &ffd);
if (hFind == INVALID_HANDLE_ VALUE)
{
dwError = GetLastError();
if (dwError == ERROR_PATH_NOT_ FOUND)
_tprintf (TEXT("[Error] Directory not found\n");
else
_tprintf (TEXT("FindFirs tFile failed (%u)\n", dwError);
return dwError;
}
else
{
_tprintf(TEXT ("File name : %s\n"), ffd.cFileName);
if (sscanf_s (ffd.cFileName, "%16s.%3s", filename, ext) == 2)
{
printf("File Name : %s\n", filename);
printf("Extensi on : %s\n", ext);
}
else
printf ("sscanf_s failed\n");
}
}

And I got a compile-time error message saying "error C2664 : 'sscanf_s' cannot convert parameter 1 from 'WCHAR [260]' to 'const char *' Types pointed to are unrelated; conversion requires reinterpret_cas t, C-stype cast or function-style cast.

Could anyone please help me fix this compile-time error?

Thank you very much for your help.

Akino

[gpraghuram]

Hi,
The variable cFileName is of type TCHAR.
This is what i see in the TCHAR definition when searching in MSDN.

#ifdef Unicode
typedef WCHAR TCHAR;
#else
typedef CHAR TCHAR;
#endif

Since the WCHAR is used you cant typecast it to char*.
So dont define Unicode and after that u can convert to char*

Raghuram

[weaknessforcats]

You can't use sscanf(). Nor can you use char or char*:

char filename[128]; <--- ERROR
char ext[128]; <--- ERROR

You have to use TCHAR.
[code=cpp]
TCHAR filename[128];
TCHAR ext[128];
[/code]


sscanf() only works with char. When Unicode is defined it has to work with wchar_t, which is WCHAR. TCHAR maps between char and wchar_t based on the Unicode settin gin your build.

The TCHAR compatible sscanf() is _stscanf().

Read this: http://msdn.microsoft.com/en-us/library/ms860358.aspx.

Your code should be:
[code=cpp]
if (_stscanf_s (ffd.cFileName, TEXT("%16s.%3s" , filename, ext) == 2)
{
[/code]

And lastly, the printf() have to be got rid of:
[code=cpp]
_tprintf(TEXT(" File Name : %s\n"), filename);
_tprintf(TEXT(" Extension : %s\n"), ext);
etc...
[/code]

Remember, with TCHAR you cannot ever use the native type char or wchat_t.