include/reactos/compat_undoc.h

#ifndef COMPAT_UNDOC_H
#define COMPAT_UNDOC_H


typedef struct _ReactOS_ShimData
{
    DWORD dwReserved1[130];
    DWORD dwSize;
    DWORD dwMagic;
    DWORD dwReserved2[242];
    DWORD dwRosProcessCompatVersion;
} ReactOS_ShimData;


#define REACTOS_SHIMDATA_MAGIC  0xAC0DEDAB
#define REACTOS_COMPATVERSION_UNINITIALIZED 0xfffffffe
#define REACTOS_COMPATVERSION_IGNOREMANIFEST 0xffffffff

// Returns values in the form of _WIN32_WINNT_VISTA, _WIN32_WINNT_WIN7 etc
static
inline
DWORD RosGetProcessCompatVersion(VOID)
{
    static DWORD g_CompatVersion = REACTOS_COMPATVERSION_UNINITIALIZED;
    if (g_CompatVersion == REACTOS_COMPATVERSION_UNINITIALIZED)
    {
        ReactOS_ShimData* pShimData = (ReactOS_ShimData*)NtCurrentPeb()->pShimData;
        if (pShimData && pShimData->dwMagic == REACTOS_SHIMDATA_MAGIC &&
            pShimData->dwSize == sizeof(ReactOS_ShimData))
        {
            g_CompatVersion = pShimData->dwRosProcessCompatVersion;
        }
    }
    return g_CompatVersion < REACTOS_COMPATVERSION_UNINITIALIZED ? g_CompatVersion : 0;
}

static
inline
UINT RosGetProcessEffectiveVersion(VOID)
{
    PPEB peb = NtCurrentPeb();
    UINT shimVer = RosGetProcessCompatVersion();
    if (shimVer)
        return shimVer;
    else
        return (peb->OSMajorVersion << 8) | (peb->OSMinorVersion);
}

#endif // COMPAT_UNDOC_H