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This article is mainly about "how to use IntPtr of c #". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn "how to use IntPtr of c #"!

In ccalldll2.cpp:

Int retstruct (user* uther int xm int y)

{

U-> id + = 10 + x

U-> age + = 10 + y

Return 0

}

In c#:

[DllImport ("ccalldll2.dll", EntryPoint = "retstruct", CallingConvention=CallingConvention.Cdecl)]

Public static extern int retstruct (IntPtr ptrUser, int x, int y); / / only ccalldll2 is referenced in the reference, and ccalldll2 uses cSharpDLLforJNA. Is that a problem?

[StructLayout (LayoutKind.Sequential)]

Struct user

{

Public int id

Public int age

}

Private void btnInptr_Click (object sender, EventArgs e)

{

User u = new user ()

U.id = 5

U.age = 7

/ / first, memory space is allocated through Marshal, and unmanaged space is allocated according to the size of user.

Int size = Marshal.SizeOf (u); / / for value types, Sizeof (variable), and for reference types, Sizeof (typeof (TYPE))

IntPtr ptruser = Marshal.AllocHGlobal (size); / / allocate memory

/ / copy the value of u to ptruser space

Marshal.StructureToPtr (u, ptruser, false)

Int res = retstruct (ptruser, 5,5); / / call the function retstruct in DLL to handle the id and age in the user referred to by the ptruser pointer.

User U2 = (user) Marshal.PtrToStructure (ptruser, typeof (user)); / / convert the processed ptruser to user

Console.WriteLine (u2.id + ":" + u2.age)

Console.WriteLine (res+ ":" + u.id + ":" + u.age)

Marshal.FreeHGlobal (ptruser)

}

Display the results:

20:22

0:5:7

At this point, I believe you have a deeper understanding of "how to use the IntPtr of c #". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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