Where is InitPropVariantFromString?

[AArnott]

Discussed in microsoft/CsWin32#1234

^{Originally posted by optsing July 10, 2024}
If I add InitPropVariantFromString to NativeMethods.txt, I get the warning message

Method, type or constant "InitPropVariantFromString" not found. Did you mean or "InitPropVariantFromStringVector" or "InitPropVariantFromStringAsVector"?

Why is this method missing? What is the correct way to create PROPVARIANT without it?

It's missing from the metadata, but it is a documented function.

[ChrisDenton]

From the "Requirements" section of the documentation page, it looks like it's a header-only function. So it's not actually exposed by any Windows DLLs.

[ChrisDenton]

If I look at the mentioned propvarutil.h I see:

win32metadata/generation/WinSDK/RecompiledIdlHeaders/um/propvarutil.h

Lines 497 to 517 in f1c1df8

	// Creates a VT_LPWSTR propvariant.
	inline HRESULT InitPropVariantFromString(_In_ PCWSTR psz, _Out_ PROPVARIANT *ppropvar)
	{
	HRESULT hr = psz != nullptr ? S_OK : E_INVALIDARG; // Previous API behavior counter to the SAL requirement.
	if (SUCCEEDED(hr))
	{
	SIZE_T const byteCount = static_cast<SIZE_T>((wcslen(psz) + 1) * sizeof(*psz));
	V_UNION(ppropvar, pwszVal) = static_cast<PWSTR>(CoTaskMemAlloc(byteCount));
	hr = V_UNION(ppropvar, pwszVal) ? S_OK : E_OUTOFMEMORY;
	if (SUCCEEDED(hr))
	{
	memcpy_s(V_UNION(ppropvar, pwszVal), byteCount, psz, byteCount);
	V_VT(ppropvar) = VT_LPWSTR;
	}
	}
	if (FAILED(hr))
	{
	PropVariantInit(ppropvar);
	}
	return hr;
	}

[AArnott]

Interesting observation about being an inline function. I suspect that's why the clang scanner missed it. The metadata doesn't expect to include macros most of the time, but I don't know about these inline functions.

[riverar]

InitPropVariantFromString is a header-only helper function. It's not available for use outside of C++.