Undefined symbol when Calling function in C++ Random Char added - c++

Question

In NodeJS I'm building an interface to a shared object in C. I have the following code:
#include <node.h>
#include "libcustom_encryption.h"
namespace demo {
using v8::Exception;
using v8::FunctionCallbackInfo;
using v8::Isolate;
using v8::Local;
using v8::Number;
using v8::Object;
using v8::String;
using v8::Value;
//
// This is the implementation of the "add" method
// Input arguments are passed using the
// const FunctionCallbackInfo<Value>& args struct
//
void DeviceGetVersion(const FunctionCallbackInfo<Value>& args)
{
char ver[10] = {0};
unsigned int ver_size = 0;
device_get_version(ver, ver_size);
Isolate* isolate = args.GetIsolate();
//
// 1. Save the value in to a isolate thing
//
Local<Value> str = String::NewFromUtf8(isolate, "Test");
//
// 2. Set the return value (using the passed in
// FunctionCallbackInfo<Value>&)
//
args.GetReturnValue().Set(str);
}
void Init(Local<Object> exports)
{
NODE_SET_METHOD(exports, "devicegetversion", DeviceGetVersion);
}
NODE_MODULE(addon, Init)
}
node-gyp configure: works
node-gyp build: works
LD_LIBRARY_PATH=libs/ node index.js: doesn't work
I get the following error:
node: symbol lookup error: /long_path/build/Release/app.node: undefined symbol: _Z18device_get_versionPcS_Phj
The when the function is called it gets prepended and appended with random characters. I'm assuming this is random data are some noise from memory. It seams as if the size brakes to call the function is bigger then it should.
I'm not that experienced with mixing C++ and C, I would love to get an explanation on what is happening hear.
Tech specs:
GCC Version: gcc version 4.8.5 20150623 (Red Hat 4.8.5-4) (GCC)
NodeJS Version: v6.2.0

Answer 1

the function is called it gets prepended and appended with random characters
It is called
name mangling that happens in C++.
The actual error here is that compiled module can not link to function device_get_version().
Your possible actions:
add the implementation of device_get_version to your module
properly link this function
simply remove that line and the error will disappear
UPD.
device_get_version may actually be a C function which is treated as a C++ function (you can tell it by mangled name it has).
Make sure your function declared as
extern "C" {
void device_get_version(...);
}