Question

I am trying to compile a program in Visual Studio 2010 in Windows 7. I am getting a compilation error C2061: syntax error: identifier ‘KNOWN_FOLDER_FLAG’ in Windows header shlobj.h at the marked line:

#if (NTDDI_VERSION >= NTDDI_VISTA)

typedef enum
{
    KF_FLAG_DEFAULT         = 0x00000000,
    KF_FLAG_CREATE          = 0x00008000,
    KF_FLAG_DONT_VERIFY     = 0x00004000,
    KF_FLAG_DONT_UNEXPAND   = 0x00002000,
    KF_FLAG_NO_ALIAS        = 0x00001000,
    KF_FLAG_INIT            = 0x00000800,
    KF_FLAG_DEFAULT_PATH    = 0x00000400,
    KF_FLAG_NOT_PARENT_RELATIVE = 0x00000200,
    KF_FLAG_SIMPLE_IDLIST   = 0x00000100,
    KF_FLAG_ALIAS_ONLY      = 0x80000000,
} KNOWN_FOLDER_FLAG;


DEFINE_ENUM_FLAG_OPERATORS(KNOWN_FOLDER_FLAG);

STDAPI SHGetKnownFolderIDList(__in REFKNOWNFOLDERID rfid,
                              __in DWORD /* KNOWN_FOLDER_FLAG */ dwFlags,
                              __in_opt HANDLE hToken,
                              __deref_out PIDLIST_ABSOLUTE *ppidl);

STDAPI SHSetKnownFolderPath(__in REFKNOWNFOLDERID rfid,
                            __in DWORD /* KNOWN_FOLDER_FLAG */ dwFlags,
                            __in_opt HANDLE hToken,
                            __in PCWSTR pszPath);

STDAPI SHGetKnownFolderPath(__in REFKNOWNFOLDERID rfid,
                            __in DWORD /* KNOWN_FOLDER_FLAG */ dwFlags,
                            __in_opt HANDLE hToken,
                            __deref_out PWSTR *ppszPath);

#endif  // NTDDI_VISTA

#if (NTDDI_VERSION >= NTDDI_WIN7)

STDAPI SHGetKnownFolderItem(__in REFKNOWNFOLDERID rfid,
                            __in KNOWN_FOLDER_FLAG flags, <<<ERROR AT THIS LINE
                            __in_opt HANDLE hToken,
                            __in REFIID riid,
                            __deref_out void **ppv);
#endif // NTDDI_WIN7

In my program the version macros is defined as folows

#define NTDDI_VERSION NTDDI_WINXP

What can be the reason for it not to compile?

It seems to me that the part I am getting the error in must not be compiled at all, but it somehow does.

Answer 1

There is only one logical conclusion: for some reason the expansion of NTDDI_VERSION when this header is compiled is not what you think it is.

Try troubleshooting by searching for #undef NTDDI_VERSION and making a clean build of your project (might be relevant if you are using precompiled headers).