Cannot take the address of the given expression
You can take the address of fields, local variables, and indirection of pointers, but you cannot take, for example, the address of the sum of two local variables.
The following sample generates CS0211:
public class a { unsafe public void mf() { int a = 0, b = 0; int *i = &(a + b); // CS0211, the addition of two local variables // try the following line instead // int *i = &a; } public static void Main() { } }