Import in C# bundle written in c++ (Unity3D project)

Question

I try to use the functions from a .bundle file inside Unity3D but every time when I call the functions I get the error:

DllNotFoundException: libant
connectANT.Start () (at Assets/connectANT.cs:13)

This is the script that I use to call the library antlib.bundle which is in the Assets/Plugin folder:

using UnityEngine;
using System.Collections;
using System.Runtime.InteropServices;

public class connectANT : MonoBehaviour {
[DllImport("libant")] static extern bool ANT_Init(int ucUSBDeviceNum_, int ulBaudrate_); 
void Start () {
    ANT_Init (1, 50000);
}
}

in the bundle this function is declared like this:

#ifdef __cplusplus
extern "C" {
#endif
EXPORT BOOL ANT_Init(UCHAR ucUSBDeviceNum_, ULONG ulBaudrate_);  //Initializes and opens USB connection to the module
#ifdef __cplusplus
}
#endif

This is just an example with only one function from the bundle. If I just import the functions in my script I don't get any error in Unity. Can someone help me to figure it out?

Sam Sam · Accepted Answer · 2015-03-17T01:26:07

try this:

[DllImport("antlib.bundle")]
static extern int ANT_Init(byte ucUSBDeviceNum_, uint ulBaudrate_);

there're two problems in your code:

wrong file name
wrong argument type and return type

if you want to use bool as return type, another attribute is required:

[return: System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.Bool)]
[DllImport("antlib.bundle")]
static extern bool ANT_Init(byte ucUSBDeviceNum_, uint ulBaudrate_);

Import in C# bundle written in c++ (Unity3D project)

2 Answers