1 struct Test1
2 {
3 int test1;
4 char test2;
5 __int64 test3;
6 short test4;
7 };
8
9 Test1 * __stdcall GetTest1()
10 {
11 test1.test1 = 10;
12 test1.test2 = 11;
13 test1.test3 = 12;
14 test1.test4 = 13;
15 return &test1;
16 }

1 [StructLayout(LayoutKind.Explicit)]
2 public struct Test
3 {
4 [FieldOffset(0)]
5 public int test1;
6 [FieldOffset(4)]
7 public char test2;
8 [FieldOffset(8)]
9 public Int64 test3;
10 [FieldOffset(16)]
11 public short test4;
12 }
13
14 [StructLayout(LayoutKind.Sequential)]
15 public struct Test1
16 {
17 public int test1;
18 public char test2;
19 public Int64 test3;
20 public short test4;
21 }
22
23 [DllImport("TestDll")]
24 public static extern IntPtr GetTest1();
25
26 //#################################
27   IntPtr p = GetTest1();
28 Test test = (Test)Marshal.PtrToStructure(p, typeof(Test));
29 Console.WriteLine(test.test1 + test.test2 + test.test3 + test.test4);
30
31 IntPtr p1 = GetTest1(); //Auto pack
32   Test1 test1 = (Test1)Marshal.PtrToStructure(p1, typeof(Test1));
33 Console.WriteLine(test1.test1 + test1.test2 + test1.test3 + test1.test4);

1 #pragma pack(1)
2  struct Test2
3 {
4 int test1;
5 char test2;
6 __int64 test3;
7 short test4;
8 };
9  #pragma pack()
10
11  #pragma pack(2)
12  struct Test3
13 {
14 int test1;
15 char test2;
16 __int64 test3;
17 short test4;
18 };
19  #pragma pack()
20
21
22  #pragma pack(4)
23  struct Test4
24 {
25 int test1;
26 char test2;
27 __int64 test3;
28 short test4;
29 };
30  #pragma pack()

1 [StructLayout(LayoutKind.Sequential, Pack = 1)]
2 struct Test2
3 {
4 public int test1;
5 public char test2;
6 public Int64 test3;
7 public short test4;
8 }
9
10 [StructLayout(LayoutKind.Sequential, Pack = 2)]
11 struct Test3
12 {
13 public int test1;
14 public char test2;
15 public Int64 test3;
16 public short test4;
17 }
18
19 [StructLayout(LayoutKind.Sequential, Pack = 4)]
20 struct Test4
21 {
22 public int test1;
23 public char test2;
24 public Int64 test3;
25 public short test4;
26 }
27
28
29 [DllImport("TestDll")]
30 public static extern IntPtr GetTest2();
31
32 [DllImport("TestDll")]
33 public static extern IntPtr GetTest3();
34
35 [DllImport("TestDll")]
36 public static extern IntPtr GetTest4();
37
38 //#################################
39   IntPtr p2 = GetTest2(); //pack 1
40   Test2 test2 = (Test2)Marshal.PtrToStructure(p2, typeof(Test2));
41
42 IntPtr p3 = GetTest3(); //pack 2
43   Test3 test3 = (Test3)Marshal.PtrToStructure(p3, typeof(Test3));
44
45 IntPtr p4 = GetTest4(); //pack4
46   Test4 test4 = (Test4)Marshal.PtrToStructure(p4, typeof(Test4));
47
48 Console.WriteLine(test2.test1 + test2.test2 + test2.test3 + test2.test4);
49 Console.WriteLine(test3.test1 + test3.test2 + test3.test3 + test3.test4);
50 Console.WriteLine(test4.test1 + test4.test2 + test4.test3 + test4.test4);