Build errors: “cannot find target for file” and “undefined reference”

Question

I am using codeblock and my compiler setting is [-std=c++0x]. I created a simple project with the following code:

main.cpp

#include <iostream>
#include "Cat.h"
using namespace std;

int main() {
    Cat action;
    action.meow();
    action.jump();
    return 0;
}

Cat.h

#ifndef CAT_H_INCLUDED
#define CAT_H_INCLUDED

class Cat {
public:
    void meow();
    void jump();
};
#endif // CAT_H_INCLUDED

CatProcess.cpp

#include <iostream>
#include "Cat.h"
using namespace std;

void Cat::meow() {
    cout << "meow" << endl;
}
void Cat::jump() {
    cout <<"jump" << endl;
}

Error messages:

When I build and run the entire project, this error shows up on main.cpp line 8 on my IDE:

undefined reference to 'Cat::meow()'

When I build and run CatProcess.cpp, this error shows up:

error: Cannot find target for file

Build log:

mingw32-g++.exe -Wall -fexceptions -g -std=c++0x -c C:\Users\Im_so\Documents\CodeBlock_Projects\ClassesForCats\main.cpp -o obj\Debug\main.o

obj\Debug\main.o: In function 'main': C:/Users/Im_so/Documents/CodeBlock_Projects/ClassesForCats/main.cpp:8: undefined reference to 'Cat::meow()'

C:/Users/Im_so/Documents/CodeBlock_Projects/ClassesForCats/main.cpp:9: undefined reference to 'Cat::jump()'

collect2.exe: error: ld returned 1 exit status

whitebatman2 whitebatman2 · Accepted Answer · 2018-06-05T10:50:38

By default in Code::Blocks when you create new source file it isn't added to any build target. When creating file there are two checkboxes - Debug and Release. If you want to add already created file to a target, right-click on the file in codeblocks -> Properties -> Build and check Debug and Release.

Build errors: “cannot find target for file” and “undefined reference”

1 Answers