How to see list of generated SafeHandle types.

[mjr4077au]

While discussing microsoft/win32metadata#2173 (comment), Jevan mentioned MsiCloseHandleSafeHandle casually as if it was known/visible somewhere. It was unknown to me until I added a particular method to NativeMethods.txt that happened to generate it. Up until that point, I rolled my own SafeHandle type for this.

For instance, I'd like to know if there's a SafeHandle type defined already for NetApiBufferFree() so I don't have to roll my own. The only method I'm using currently is NetGetJoinInformation() and it outs a PWSTR, so no SafeHandle has been generated.

[jevansaks]

That's a good question! I have been meaning to write more documentation for some of this stuff (there's another issue tracking that) but basically cswin32 will generate a SafeHandle type for any type that has an [RAIIFree(...)] annotation on it in the win32metadata (go see https://github.com/microsoft/win32metadata readme for how to browse the metadata with ilspy).

In this case I saw the MSIHANDLE had RAIIFree for MsiCloseHandle, hence if any function needs MSIHANDLE then CsWin32 will generate the safehandle.

But this brings up an interesting idea: we could probably generate a SafeHandle for any function you ask for as long as it's HANDLE-like and takes one parameter. E.g. I've wanted a LocalFreeSafeHandle even though there's no metadata that would cause one to be generated yet.

[mjr4077au]

I really do need to immerse myself more into the win32metadata as it would be good to contribute my own fixes rather than just reporting them. It's the age of story of time, family, prioritisation, etc.

FWIW though, CsWin32 does generate a LocalFreeSafeHandle and I use it within my projects where relevant: https://github.com/search?q=repo%3APSAppDeployToolkit%2FPSAppDeployToolkit%20LocalFreeSafeHandle&type=code Ignore this, I read into what you said too literally 😅

Perhaps at the very least, ensuring when a native method that frees a handle is added, such as LocalFree, etc, a SafeHandle is defined for that. More often than not, this isn't the case and it's only when you by luck include a native method that has a friendly SafeHandle overload do you get one, just like with the MSI stuff I mentioned.