MonoPInvokeCallbackAttribute Class

Reference

Definition

Namespace:: ObjCRuntime

Assembly:: Xamarin.iOS.dll

Assembly:: Xamarin.Mac.dll

Important

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Attribute used to annotate functions that will be called back from the unmanaged world.

[System.AttributeUsage(System.AttributeTargets.Method)]
public sealed class MonoPInvokeCallbackAttribute : Attribute

type MonoPInvokeCallbackAttribute = class
    inherit Attribute

Inheritance: Attribute
MonoPInvokeCallbackAttribute

Attributes: AttributeUsageAttribute

Remarks

This attribute is valid on static functions and it is used by Mono's Ahead of Time Compiler to generate the code necessary to support native call calling back into managed code.

In regular ECMA CIL programs this happens automatically, and it is not necessary to flag anything specially, but with pure Ahead of Time compilation the compiler needs to know which methods will be called from the unmanaged code.

In the current version of Xamarin.iOS, only static functions can be called back from unmanaged code.

You must specify the type of the delegate that this code will be called as. The following example shows the scenario in which this is used:

using System;
	delegate void DrawPatternCallback (IntPtr voidptr, IntPtr cgcontextref);

	[MonoPInvokeCallback (typeof (DrawPatternCallback))]
	static void DrawCallback (IntPtr voidptr, IntPtr cgcontextptr)
	{
		// This method is called from the C library
	}

Constructors

MonoPInvokeCallbackAttribute(Type)

Constructor for the MonoPInvokeCallbackAttribute.

Properties

DelegateType

The type of the delegate that will be calling us back.

Applies to