nethost Hosting Sample- Invoking simple method via load_assembly_and_get_function_pointer

[comeradealexi]

Apologies if this is the incorrect place for this question but I think I'm missing something in how load_assembly_and_get_function_pointer from the hosting example works.

In the hosting example it uses load_assembly_and_get_function_pointer to get a pointer to the C# method: public static int Hello(IntPtr arg, int argLength) which works fine.

In my tests though, I want to just invoke a more simple method: public static void HelloSimple() but I'm unable to get this to work, load_assembly_and_get_function_pointer will return error code (-2147024809 / 0x80070057) - I'm not 100% sure what these error codes relate to. I couldn't find them on https://github.com/dotnet/runtime/blob/main/docs/design/features/host-error-codes.md

I can easily get my methods to invoke if I ensure a parameter is passed and a value is returned. Is this some kind of requirement when invoking C# or perhaps I'm missing some additional code required to allow me to invoke more simple methods?

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Document Details

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• ID: 83da7030-b5f1-72ad-71f6-424ff45b8b7f
• Version Independent ID: a98926cc-64ab-2911-e4b8-1eaf4573dfe4
• Content: Write a custom .NET runtime host - .NET
• Content Source: docs/core/tutorials/netcore-hosting.md
• Product: dotnet-fundamentals
• GitHub Login: @mjrousos
• Microsoft Alias: tdykstra

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Associated WorkItem - 98747

[tdykstra]

@mjrousos Can you help with this question?

[mjrousos]

Hi @comeradealexi, load_assembly_and_get_function_pointer takes a parameter that specifies the delegate type name. If no delegate type is specified, then it defaults to expecting int (IntPtr args, int sizeBytes). If you want to call methods with different signatures, you should be able to just specify the delegate type to use that matches the method's signature. Additional details are available here.