From the MSDN documentation of Marshal.AllocHGlobal:
AllocHGlobal is one of two memory allocation methods in the Marshal class. This method exposes the Win32 LocalAlloc function from Kernel32.dll.
Considering there's a GlobalAlloc API which allocates memory on the global heap, rather than the local heap, isn't this method's name rather misleading?
Was there a reason for naming it AllocHGlobal, rather than AllocHLocal?
Update: Simon points out in the comments that there's no such thing as a global heap in Windows any more, and the GlobalAlloc and LocalAlloc APIs remained for legacy purposes only. These days, the GlobalAlloc API is nothing morethan a wrapper for LocalAlloc.
This explains why the API doesn't call GlobalAlloc at all, but it doesn't explain why the API was named AllocHGlobal when it doesn't (can't) use a global heap, nor does it even call GlobalAlloc. The naming cannot possibly be for legacy reasons, because it wasn't introduced until .NET 2.0, way after 16-bit support was dropped. So, the question remains: why is Marshal.AllocHGlobal so misleadingly named?
Suppose you're doing data transfer between apps using drag and drop or over the clipboard. To populate the STGMEDIUM structure you need an HGLOBAL. So you call AllocHGlobal. Hence the name.
The main use for this function is to interop with APIs that want an HGLOBAL. It would be confusing if it was called anything else because when you wanted an HGLOBAL you'd have to find some documentation to tell you that AllocAnythingElse produced a value you could use as an HGLOBAL.