g++ is failing "linker command failed with exit code 1"

Question

I'm trying to run a function from my main.cpp file that takes a string and the command-line arguments. These are what my files look like. (I've excluded the unnecessary includes and variables, because I don't think they're relevant to this issue)

main.cpp

#include "lib/run.h"

int main(int argc, char *argv[]){
    kiwi_process runfile;
    runfile.run(input, argv);
}

lib/run.h

class kiwi_process {
public:
    void run(std::string content, char** args);
};

lib/run.cpp

#include <iostream>
#include <string>
#include "run.h"

int kiwi_process::run(std::string content, char** args){
    std::cout << content;
}

I'm compiling with

g++ -o kiwi main.cpp -std=gnu++17

And it's erring

Undefined symbols for architecture x86_64:
  "kiwi_process::run(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, char**)", refere
nced from:
      _main in main-8b6378.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

What am I doing wrong?

your code is missing definition of method `kiwi_process::run`. — Marek R, May 05 '19 at 18:32
`runfile.run(input, argv);` - what is `input`? I don't see it. — Jesper Juhl, May 05 '19 at 18:33
You need to compile both source files and then link them together. — Retired Ninja, May 05 '19 at 18:33
`g++ -c -o main.o main.cpp -std=gnu++17` `g++ -c -o run.o run.cpp -std=gnu++17` `g++ -o kiwi main.o run.o` — Marek R, May 05 '19 at 18:39
@MarekR Just `g++ -o kiwi main.cpp lib/run.cpp -std=gnu++17` will do — Lightness Races in Orbit, May 05 '19 at 18:46

g++ is failing "linker command failed with exit code 1"

0 Answers0