CODEWITHSUNDEEP
c++
elefante
elefante

Reputation: 105

(.bss+0x0): multiple definition of Proxies

I have this code for automating a robot. It uses some proxy classes from Player - an open-source software for programming robots. I compiled the two cpp files using these commands:

g++ -c -Wall  navigation.cpp `pkg-config --cflags playerc++` `pkg-config --libs playerc++`
and
g++ -c -Wall  autonavigation.cpp `pkg-config --cflags playerc++` `pkg-config --libs playerc++`
I then linked the object files (which is where the problem arises):
g++ -o autonavigate  navigation.o autonavigation.o `pkg-config --cflags playerc++` `pkg-config --libs playerc++`.

The code is here:

erratic@erratic-desktop:~/Desktop/autonav$ g++ -o autonavigate navigation.o 
autonavigation.o `pkg-config --cflags playerc++` `pkg-config --libs playerc++`

autonavigation.o:(.bss+0x0): multiple definition of `gHostname'

navigation.o:(.bss+0x0): first defined here

autonavigation.o:(.data+0x0): multiple definition of `gPort'

navigation.o:(.data+0x0): first defined here

autonavigation.o:(.bss+0x4): multiple definition of `gIndex'

navigation.o:(.bss+0x4): first defined here

autonavigation.o:(.bss+0x8): multiple definition of `gDebug'

navigation.o:(.bss+0x8): first defined here

autonavigation.o:(.data+0x4): multiple definition of `gFrequency'

navigation.o:(.data+0x4): first defined here

autonavigation.o:(.data+0x8): multiple definition of `gDataMode'

navigation.o:(.data+0x8): first defined here

autonavigation.o:(.bss+0xc): multiple definition of `gUseLaser'

navigation.o:(.bss+0xc): first defined here

autonavigation.o: In function `parse_args(int, char**)':

autonavigation.cpp:(.text+0x0): multiple definition of `parse_args(int, char**)'

navigation.o:navigation.cpp:(.text+0x0): first defined here

autonavigation.o: In function `print_usage(int, char**)':

autonavigation.cpp:(.text+0x101): multiple definition of `print_usage(int, char**)'

navigation.o:navigation.cpp:(.text+0x101): first defined here

collect2: ld returned 1 exit status

Source code from comment:

//navigation.h
#include <libplayerc++/playerc++.h>
#include <stdio.h>
#include <time.h>
#include "args.h"
#define PI 3.14159

using namespace std;
using namespace PlayerCc;

class navigation
{
public:
    navigation();
    void autoNavigate(PlayerClient &, LaserProxy &, Position2dProxy &, PtzProxy &, IrProxy &, SonarProxy &);

private:
    void wallFollow(LaserProxy &, Position2dProxy &);
    void obstacleAvoid(IrProxy &, SonarProxy &, PlayerClient &, Position2dProxy &);
};

Source for autonavigation.cpp:

#include "navigation.h"

int main(int argc, char *argv[])
{
    PlayerClient robot("localhost");
    LaserProxy lp(&robot,0);
    Position2dProxy pp(&robot,0);
    PtzProxy ptp (&robot,0);
    IrProxy ir(&robot,0);
    SonarProxy sp(&robot, gIndex);

    navigation nav;
    nav.autoNavigate(robot, lp, pp, ptp, ir, sp);
}

Upvotes: 5

Views: 11308

Answers (1)

Some programmer dude
Some programmer dude

Reputation: 409166

Without seeing your code we can only guess, but my guess is that you define these variables in a header file that you include in both source files.

You should declare the variables, and be using extern to tell the compiler that the variables are defined somewhere else. Then in one source file you define the variables (i.e. the same as the declarations in the header file but without the extern keyword).

For example, lets say I have a variable hostname that I want to use in multiple source files, then I make an extern declaration in a header file that I include in all source files that needs the variable:

extern char hostname[32];

Then in one source file I define the variable:

char hostname[32];

Upvotes: 7

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