Error undefined reference to `BP::Device::Create(std::string const&)'

Question

I have a file.cpp which i'm porting to linux from windows. I've changed all the specific headers and functions, but I still got this error. here's my code.

#define _CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES 1
#define _CRT_SECURE_NO_DEPRECATE 1

#include <stdio.h>
#include <curses.h>
#include <termios.h>
#include <term.h>
#include <unistd.h>

#include "BioPlux.h"

#define BUF_SIZ 1000

static struct termios initial_settings, new_settings;
static int peek_character = -1;

int kbhit();

int kbhit()
{
    char ch;
    int nread;

    if(peek_character != -1)
        return 1;
    new_settings.c_cc[VMIN]=0;
    tcsetattr(0, TCSANOW, &new_settings);
    nread = read(0,&ch,1);
    new_settings.c_cc[VMIN]=1;
    tcsetattr(0, TCSANOW, &new_settings);

    if(nread == 1) {
        peek_character = ch;
        return 1;
    }
    return 0;
}

int main()
{
   BP::Device::Frame frames[BUF_SIZ];

   FILE *f = fopen("teste.txt", "w");

   BP::Device *dev = NULL;

   try
   {
      // decomment next block to search for bioPlux devices
      /*
      std::vector<std::string> devs;
      BP::Device::FindDevices(devs);
      fprintf(f, "FindDevices: %d\n", devs.size());
      for(int i=0; i < devs.size(); i++)
          fprintf(f, "%s\n", devs[i].c_str());
      */

      dev = BP::Device::Create("00:07:80:40:DD:D8");  // put here the MAC address of your device

      std::string str;
      dev->GetDescription(str);
      printf("Description: %s\n", str.c_str());
      fprintf(f, "# Description: %s\n", str.c_str());

      dev->SetDOut(true); // put the digital output at HIGH - useless

      dev->BeginAcq(); // 1000 Hz, 12 bits, 6/8 channels
      //dev->BeginAcq(1000, 0x01, 12); // 1000 Hz, 12 bits, channel 1 only

      //for(int k = 0; k < 10; k++) // total 10 seconds
      while(!kbhit())
      {
         dev->GetFrames(BUF_SIZ, frames); // block for 1 sec
         putchar('*');
         for(int i=0; i < BUF_SIZ; i++) // while the data to file
         {
            fprintf(f, "%i", frames[i].seq);
            for(int j = 0; j < 8; j++)
               fprintf(f, "\t%i", frames[i].an_in[j]);
            fputc('\n', f);
         }
      }      

      dev->EndAcq();
   } // end try

   catch (BP::Err err)
   {
      char const *typ;
      switch(err.GetType())
      {
      case BP::Err::TYP_ERROR:
         typ = "Error";
         break;
      case BP::Err::TYP_NOTIFICATION:
         typ = "Notification";
         break;
      }
      printf("Error: %d Type: %s - %s\n", err.code, typ, err.GetDescription());
   }

   if (dev) delete dev;
    fclose(f);
   return 0;
}

this is the file.cpp which includes the following header above. The class is defined in here.

#include <vector>
#include <string>
#include <inttypes.h>

typedef unsigned char    BYTE;
typedef unsigned short   WORD;

#ifndef _BIOPLUXHEADER_
#define _BIOPLUXHEADER_

namespace BP
{
   class Device
   {
   public:
      struct Frame
      {
         BYTE  seq;
         bool  dig_in;
         WORD  an_in[8];
      };

      static void    FindDevices(std::vector<std::string> &devs);
      static Device* Create(const std::string &port);

      virtual void   GetDescription(std::string &str)=0;
      virtual void   BeginAcq(void)=0;
      virtual void   BeginAcq(int freq, BYTE chmask, BYTE nbits)=0;
      virtual void   GetFrames(int nframes, Frame *frames)=0;
      virtual void   SetDOut(bool dout)=0;
      virtual void   EndAcq(void)=0;
      virtual        ~Device() {}
   };

   class Err
   {
   public:
      enum Code {
         // Notifications
           //BT_AUTHENTICATION,
           BT_ADDRESS = 1,
           BT_ADAPTER_NOT_FOUND,
           BT_DEVICE_NOT_FOUND,
           CONTACTING_DEVICE,
           PORT_COULD_NOT_BE_OPENED,
         // Errors
           PORT_INITIALIZATION,
           //FIRMWARE_NOT_SUPPORTED,
           DEVICE_NOT_IDLE,
           DEVICE_NOT_IN_ACQUISITION_MODE,
           PORT_COULD_NOT_BE_CLOSED,
           BT_DEVICE_NOT_PAIRED,
         INVALID_PARAMETER,
         FUNCTION_NOT_SUPPORTED
      } code;

      enum Type {
         TYP_ERROR,
         TYP_NOTIFICATION
      };

      Err(Code c) : code(c) {}
      Type        GetType(void);
      const char* GetDescription(void);
   };
}

#endif

this is an outpu from the compilation try:

samuelpedro@ubuntu:~/Desktop/bioPlux API/C++$ g++ -o bttest_simple bttest_simple.cpp -lbluetooth BioPlux.lib
/tmp/cccJUI8I.o: In function `main':
bttest_simple.cpp:(.text+0xf8): undefined reference to `BP::Device::Create(std::string const&)'
bttest_simple.cpp:(.text+0x426): undefined reference to `BP::Err::GetType()'
bttest_simple.cpp:(.text+0x459): undefined reference to `BP::Err::GetDescription()'
collect2: error: ld returned 1 exit status

Answer 1

Your definition of class BP::Device contains a declaration of a method named Create() , but no code for it, so it has to be defined in some source file somewhere. Does your Windows build include a source file with its definition? Because your link apparently does not include that file, if it exists. If you're using Visual Studio, you'll have to add that file to your project, or else add a library that includes it.