UnmanagedCallConvAttribute Class

Definition

Namespace:

System.Runtime.InteropServices

Assembly:

System.Runtime.InteropServices.dll

Source:

UnmanagedCallConvAttribute.cs

Specifies the calling convention required to call P/Invoke methods implemented in unmanaged code.

public ref class UnmanagedCallConvAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Method, AllowMultiple=false, Inherited=false)]
public sealed class UnmanagedCallConvAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Method, AllowMultiple=false, Inherited=false)>]
type UnmanagedCallConvAttribute = class
    inherit Attribute

Public NotInheritable Class UnmanagedCallConvAttribute
Inherits Attribute

Inheritance

Object

Attribute

UnmanagedCallConvAttribute

Attributes

AttributeUsageAttribute

Examples

The following examples declare P/Invokes using the UnmanagedCallConvAttribute to specify the calling convention.

Using the cdecl calling convention:

// Target will be invoked using the cdecl calling convention
[UnmanagedCallConv(CallConvs = new Type[] { typeof(CallConvCdecl) })]
[DllImport("NativeLibrary", EntryPoint = "native_function_cdecl")]
internal static extern int NativeFunction(int arg);

// Target will be invoked using the cdecl calling convention and with the GC transition suppressed
[UnmanagedCallConv(CallConvs = new Type[] { typeof(CallConvCdecl), typeof(CallConvSuppressGCTransition) })]
[DllImport("NativeLibrary", EntryPoint = "native_function_cdecl")]
internal static extern int NativeFunction_NoGCTransition(int arg);

Using the stdcall calling convention:

// Target will be invoked using the stdcall calling convention
[UnmanagedCallConv(CallConvs = new Type[] { typeof(CallConvStdcall) })]
[DllImport("NativeLibrary", EntryPoint = "native_function_stdcall")]
internal static extern int NativeFunction(int arg);

// Target will be invoked using the stdcall calling convention and with the GC transition suppressed
[UnmanagedCallConv(CallConvs = new Type[] { typeof(CallConvStdcall), typeof(CallConvSuppressGCTransition) })]
[DllImport("NativeLibrary", EntryPoint = "native_function_stdcall")]
internal static extern int NativeFunction_NoGCTransition(int arg);

Remarks

When this attribute is applied to a method with DllImportAttribute where CallingConvention is either not set or set to Winapi, the .NET runtime will use CallConvs to determine the calling convention of the P/Invoke.

This attribute is ignored if applied to a method without DllImportAttribute or with CallingConvention set to something other than Winapi.

Constructors

UnmanagedCallConvAttribute()

Initializes a new UnmanagedCallConvAttribute instance.

Fields

CallConvs

Optional. Types indicating calling conventions for the unmanaged target.

Properties

TypeId

When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)

Methods

Equals(Object)	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute)
GetHashCode()	Returns the hash code for this instance. (Inherited from Attribute)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsDefaultAttribute()	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute)
Match(Object)	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)