WinReg v1.0

High-level C++ Wrappers Around Low-level Windows Registry C-interface APIs

by Giovanni Dicanio

The Windows Registry C-interface API is very low-level and hard to use.

I developed some C++ wrappers around this low-level Win32 API, to raise the semantic level, using C++ classes like std::wstring, std::vector, etc. instead of raw C-style buffers and low-level mechanisms.

For example, the REG_MULTI_SZ registry type associated to double-NUL-terminated C-style strings is handled using a much easier higher-level vector<wstring>. My C++ code does the translation between high-level C++ STL-based stuff and low-level Win32 C-interface APIs.

Moreover, Win32 error codes are translated to C++ exceptions.

The Win32 registry value types are mapped to C++ higher-level types according the following table:

Win32 Registry Type	C++ Type
REG_DWORD	DWORD
REG_QWORD	ULONGLONG
REG_SZ	std::wstring
REG_EXPAND_SZ	std::wstring
REG_MULTI_SZ	std::vector<std::wstring>
REG_BINARY	std::vector<BYTE>

I developed this code using Visual Studio 2015 with Update 3. The code compiles cleanly at /W4 in both 32-bit and 64-bit builds.

The library's code is contained in a reusable header-only WinReg.hpp file.

WinRegTest.cpp contains some demo/test code for the library: check it out for some sample usage.

The library exposes two main classes:

• RegKey: a tiny efficient wrapper around raw Win32 HKEY handles
• RegException: an exception class to signal error conditions

There are many member functions inside the RegKey class, that wrap raw Win32 registry C-interface APIs in a convenient C++ way.

For example, you can simply open a registry key and get registry values with C++ code like this:

RegKey key{ HKEY_CURRENT_USER, L"SOFTWARE\\Connie" };
DWORD dw = key.GetDwordValue(L"SomeDwordValue");
wstring s = key.GetStringValue(L"SomeStringValue");

Or you can enumerate all the values under a key with this simple code:

auto values = key.EnumValues();

The library stuff lives under the winreg namespace.

See the WinReg.hpp header for more details and documentation.