Compiler Error CS1642

Fixed size buffer fields may only be members of structs.

This error occurs if you use a fixed size buffer field in a class, instead of a struct. To resolve this error, change the class to a struct or declare the field as an ordinary array.

Example

The following sample generates CS1642.

// CS1642.cs
// compile with: /unsafe /target:library
unsafe class C
{
   fixed int a[10];   // CS1642
}

unsafe struct D
{
    fixed int a[10];
}

unsafe class E
{
   public int[] a = null;
}