Compiler Error CS0625

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'field': instance field types marked with StructLayout(LayoutKind.Explicit) must have a FieldOffset attribute

When a struct is marked with an explicit StructLayout attribute, all fields in the struct must have the FieldOffset attribute. For more information, see StructLayoutAttribute Class.

The following sample generates CS0625:

// CS0625.cs
// compile with: /target:library
using System;
using System.Runtime.InteropServices;

[StructLayout(LayoutKind.Explicit)]
struct A
{
   public int i;   // CS0625 not static; an instance field
}

// OK
[StructLayout(LayoutKind.Explicit)]
struct B
{
   [FieldOffset(5)]
   public int i;
}