Method TryGetMultiStringValue

external/WinReg/WinReg.hpp:1899–1951

inline RegExpected<std::vector<std::wstring>>
    RegKey::TryGetMultiStringValue(const std::wstring& valueName) const
{
    _ASSERTE(IsValid());

    using RegValueType = std::vector<std::wstring>;

    // Request the size of the multi-string, in bytes
    DWORD dataSize = 0;
    constexpr DWORD flags = RRF_RT_REG_MULTI_SZ;
    LSTATUS retCode = ::RegGetValueW(
        m_hKey,
        nullptr,    // no subkey
        valueName.c_str(),
        flags,
        nullptr,    // type not required
        nullptr,    // output buffer not needed now
        &dataSize
    );
    if (retCode != ERROR_SUCCESS)
    {
        return detail::MakeRegExpectedWithError<RegValueType>(retCode);
    }

    // Allocate room for the result multi-string.
    // Note that dataSize is in bytes, but our vector<wchar_t>::resize method requires size
    // to be expressed in wchar_ts.
    std::vector<wchar_t> data(dataSize / sizeof(wchar_t), L' ');

    // Read the multi-string from the registry into the vector object
    retCode = ::RegGetValueW(
        m_hKey,
        nullptr,    // no subkey
        valueName.c_str(),
        flags,
        nullptr,    // no type required
        data.data(),   // output buffer
        &dataSize
    );
    if (retCode != ERROR_SUCCESS)
    {
        return detail::MakeRegExpectedWithError<RegValueType>(retCode);
    }

    // Resize vector to the actual size returned by GetRegValue.
    // Note that the vector is a vector of wchar_ts, instead the size returned by GetRegValue
    // is in bytes, so we have to scale from bytes to wchar_t count.
    data.resize(dataSize / sizeof(wchar_t));

    // Convert the double-null-terminated string structure to a vector<wstring>,
    // and return that back to the caller
    return RegExpected<RegValueType>{ detail::ParseMultiString(data) };
}


inline RegExpected<std::vector<BYTE>>