Export (0) Print
Expand All
Expand Minimize
This topic has not yet been rated - Rate this topic

CallingConvention Enumeration

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

Namespace: System.Runtime.InteropServices
Assembly: mscorlib (in mscorlib.dll)

[SerializableAttribute] 
[ComVisibleAttribute(true)] 
public enum CallingConvention
/** @attribute SerializableAttribute() */ 
/** @attribute ComVisibleAttribute(true) */ 
public enum CallingConvention
SerializableAttribute 
ComVisibleAttribute(true) 
public enum CallingConvention
 Member nameDescription
CdeclThe caller cleans the stack. This enables calling functions with varargs, which makes it appropriate to use for methods that accept a variable number of parameters, such as Printf
FastCallThis calling convention is not supported. 
StdCallThe callee cleans the stack. This is the default convention for calling unmanaged functions with platform invoke. 
ThisCallThe first parameter is the this pointer and is stored in register ECX. Other parameters are pushed on the stack. This calling convention is used to call methods on classes exported from an unmanaged DLL. 
Supported by the .NET Compact FrameworkWinapiThis member is not actually a calling convention, but instead uses the default platform calling convention. For example, on Windows the default is StdCall and on Windows CE.NET it is Cdecl

Always use the CallingConvention enumeration rather than the CALLCONV enumeration to specify a calling convention in managed code. The latter exists only for the sake of COM definitions. The CallingConvention enumeration is used by DllImportAttribute and several classes in System.Reflection.Emit to dynamically emit platform invoke signatures.

The following example demonstrates how to apply the Cdecl calling convention, which you must use because the stack is cleaned up by the caller.

using System;
using System.Runtime.InteropServices;

public class LibWrap
{
// C# doesn't support varargs so all arguments must be explicitly defined.
// CallingConvention.Cdecl must be used since the stack is 
// cleaned up by the caller.

// int printf( const char *format [, argument]... )

[DllImport("msvcrt.dll", CharSet=CharSet.Ansi, CallingConvention=CallingConvention.Cdecl)]
public static extern int printf(String format, int i, double d); 

[DllImport("msvcrt.dll", CharSet=CharSet.Ansi, CallingConvention=CallingConvention.Cdecl)]
public static extern int printf(String format, int i, String s); 
}

public class App
{
    public static void Main()
    {
        LibWrap.printf("\nPrint params: %i %f", 99, 99.99);
        LibWrap.printf("\nPrint params: %i %s", 99, "abcd");
    }
}

import System.*;
import System.Runtime.InteropServices.*;

public class LibWrap
{
    // VJ# doesn't support varargs so all arguments must be explicitly defined.
    // CallingConvention.Cdecl must be used since the stack is 
    // cleaned up by the caller.
    // int printf( const char *format [, argument]... )
    /** @attribute DllImport("msvcrt.dll", CharSet = CharSet.Ansi, 
        CallingConvention = CallingConvention.Cdecl)
     */
    public static native int printf(String format, int i, double d);

    /** @attribute DllImport("msvcrt.dll", CharSet = CharSet.Ansi, 
        CallingConvention = CallingConvention.Cdecl)
     */
    public static native int printf(String format, int i, String s);
} //LibWrap

public class App
{
    public static void main(String[] args)
    {
        LibWrap.printf("\nPrint params: %i %f", 99, 99.99);
        LibWrap.printf("\nPrint params: %i %s", 99, "abcd");
    } //main
} //App

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0
Did you find this helpful?
(1500 characters remaining)
Thank you for your feedback

Community Additions

ADD
Show:
© 2014 Microsoft. All rights reserved.