LoadIconWithScaleDown: hinst parameted can be NULL

[Antony Male]

Actual behavior

The generated code for LoadIconWithScaleDown is:

internal static unsafe winmdroot.Foundation.HRESULT LoadIconWithScaleDown(SafeHandle hinst, string pszName, int cx, int cy, out DestroyIconSafeHandle phico)
{
	bool hinstAddRef = false;
	try
	{
		fixed (char* pszNameLocal = pszName)
		{
			winmdroot.Foundation.HINSTANCE hinstLocal;
			if (hinst is object)
			{
				hinst.DangerousAddRef(ref hinstAddRef);
				hinstLocal = (winmdroot.Foundation.HINSTANCE)hinst.DangerousGetHandle();
			}
			else
				throw new ArgumentNullException(nameof(hinst));
			winmdroot.UI.WindowsAndMessaging.HICON phicoLocal;
			winmdroot.Foundation.HRESULT __result = PInvoke.LoadIconWithScaleDown(hinstLocal, pszNameLocal, cx, cy, &phicoLocal);
			phico = new DestroyIconSafeHandle(phicoLocal, ownsHandle: true);
			return __result;
		}
	}
	finally
	{
		if (hinstAddRef)
			hinst.DangerousRelease();
	}
}

However, the documentation states that the hinst parameter can be null:

A handle to the module of either a DLL or executable (.exe) file that contains the icon to be loaded. For more information, see GetModuleHandle.

To load a predefined system icon or a standalone icon file, set this parameter to NULL.

Expected behavior

The generated LoadIconWithScaleDown allows hinst to be null.

Repro steps

1. NativeMethods.txt content:

LoadIconWithScaleDown

2. NativeMethods.json content (if present):

None.

4. Any of your own code that should be shared?

None

Context

• CsWin32 version: 0.3.106
• Win32Metadata version (if explicitly set by project): N/A
• Target Framework: net5.0-windows
• LangVersion (if explicitly set by project): 10

[Antony Male]

It looks like the same issues applies to LoadIconMetric as well

[Andrew Arnott]

Thanks for the feedback. This is a shortcoming of the metadata, which does not annotate these parameters as optional. I'll move this issue to the metadata repo so it can be corrected.