how to use cdecl callback with pinvoke

I have a c library that has cdecl callbacks. How can I use these from c#.

Everything seems to say that they must be stdcall callbacks

to be clear:

delegate int del();
[dllimport("mylib.dll",CallingConvention=CallingConvention.Cdecl)]
public static extern int funcwithcallback(del foo);

where del must be called cdecl-wise