Compiler Warning (level 1) CS0824
Constructor 'name' is marked external.
A constructor may be marked as extern. However, the compiler cannot verify that the constructor actually exists. Therefore the warning is generated.
To remove this warning
Use a pragma warning directive to ignore it.
Move the constructor inside the type.
Example
The following code generates CS0824:
// cs0824.cs
public class C
{
extern C(); // CS0824
public static int Main()
{
return 1;
}
}