PVS-Studio warning V510 for WinMerge

String GetSysError(int nerr);
...
CString msg;
msg.Format(
_T("Failed to open registry key HKCU/%s:\n\t%d : %s"),
f_RegDir, retVal, GetSysError(retVal));

Everything looks fine at the first sight. But the "String" type is nothing but "std::wstring". Therefore, we will get some gibberish printed at best and an Access Violation error at worst. An object of the "std::wstring" type is placed instead of the string pointer into the stack. The correct code should contain a call of c_str():

This suspicious code was found in WinMerge project by PVS-Studio static code analyzer.
Warning message is:
V510 The 'Format' function is not expected to receive class-type variable as 'N' actual argument

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/