Undefined Reference to <function>

[karan129]

I've googled away to figure this out, and tried out different command line combinations but the error persists. This is what happens... btw I'm new to Linux but not to C++.

chezkaranubuntu:~/Desktop/Project$ gcc -Wall modbustest.cxx -o modbustest
/tmp/ccoGrNDI.o: In function `main':
modbustest.cxx(.text+0x28): undefined reference to `initscr'
modbustest.cxx(.text+0xd0): undefined reference to `std::cout'
modbustest.cxx(.text+0xd5): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0xe4): undefined reference to `std::cout'
modbustest.cxx(.text+0xe9): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x118): undefined reference to `Mb_open_device(char*, int, int, int, int)'
modbustest.cxx(.text+0x12e): undefined reference to `std::cout'
modbustest.cxx(.text+0x133): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x146): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x156): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x19f): undefined reference to `std::cout'
modbustest.cxx(.text+0x1a4): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x20a): undefined reference to `Mb_master(Mbm_trame, int*, int*, void*, void*)'
modbustest.cxx(.text+0x22a): undefined reference to `std::cout'
modbustest.cxx(.text+0x22f): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x24d): undefined reference to `std::cout'
modbustest.cxx(.text+0x252): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x270): undefined reference to `std::cout'
modbustest.cxx(.text+0x275): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x290): undefined reference to `std::cout'
modbustest.cxx(.text+0x295): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x2b0): undefined reference to `std::cout'
modbustest.cxx(.text+0x2b5): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x2c6): undefined reference to `std::cout'
modbustest.cxx(.text+0x2cb): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x2de): undefined reference to `std::basic_ostream<char, std::char_traits<char> >::operator<<(int)'
modbustest.cxx(.text+0x2ee): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x2fd): undefined reference to `std::cout'
modbustest.cxx(.text+0x302): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x314): undefined reference to `std::cin'
modbustest.cxx(.text+0x319): undefined reference to `std::basic_istream<char, std::char_traits<char> >& std::operator>><char, std::char_traits<char> >(std::basic_istream<char, std::char_traits<char> >&, char&)'
modbustest.cxx(.text+0x354): undefined reference to `std::cout'
modbustest.cxx(.text+0x359): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x35e): undefined reference to `Mb_close_device()'
modbustest.cxx(.text+0x36d): undefined reference to `std::cout'
modbustest.cxx:(.text+0x372): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
modbustest.cxx(.text+0x377): undefined reference to `endwin'
modbustest.cxx(.text+0x37c): undefined reference to `stdscr'
modbustest.cxx(.text+0x384): undefined reference to `wgetch'
/tmp/ccoGrNDI.o: In function `__static_initialization_and_destruction_0(int, int)':
modbustest.cxx(.text+0x3c1): undefined reference to `std::ios_base::Init::Init()'
modbustest.cxx(.text+0x3c6): undefined reference to `std::ios_base::Init::~Init()'
/tmp/ccoGrNDI.o(.eh_frame+0x12): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status

The header files included are...

#include<iostream>
#include<modbus.h>
#include<ncurses.h>

Any ideas would be appreciated

[gerard4143]

try using -lncurses in your compile line


gcc -Wall modbustest.cxx -o modbustest -lncurses

Also your using gcc and std::cout is g++

So maybe try:

g++ -Wall modbustest.cxx -o modbustest -lncurses

[techieMoe]

Did you also include this line after your headers?

using namespace std;

[hazel]

I think you need to invoke gcc as g++ to compile C++ programs. Otherwise you don't get the C++ library.

[karan129]

try using -lncurses in your compile line


gcc -Wall modbustest.cxx -o modbustest -lncurses

Also your using gcc and std::cout is g++

So maybe try:

g++ -Wall modbustest.cxx -o modbustest -lncurses

Thanks, I'll try it out and report back.

Did you also include this line after your headers?

using namespace std;

Nops, I'll add it and check.

I think you need to invoke gcc as g++ to compile C++ programs. Otherwise you don't get the C++ library.

Oh yeah should've thought of that...

[karan129]

Thanks for the suggestions, they fixed most of the errors. A few errors remain to do with the modbus.h header file. I tried adding the -lmodbus switch but that didn't help. I guess I'll have to ask the author of the header file directly.

Thank you again

[karan129]

Googled some more, and it appears that for some reason I had to include the modbus.h file like this...

extern "C" {
#include "modbus.h"
}

No errors =D