Frustrated by gdb tutorials that are either too complicated or too simple? I think this might be an actually-useful tutorial to help you see how and why gdb can be useful. Anyway, it's the path I followed to finding a use for the mysterious gdb, so maybe it will work for you.

To follow along with this episode, here's some simple yet buggy code. This compiles but crashes when run.

#include <iostream>

#include <stdlib.h> // rand

#include <stdio.h> // printf

using namespace std;

int main () {

srand (time(NULL));

int penguin = rand() % 8;

cout << "This is a message from your friendly codern" << endl;

int kiwi = 3;

printf("penguin is set to is %sn", penguin);

printf("kiwi is set to is %sn", kiwi);

return 0;

} // main

To compile it and see it crash, do this:

$ g++ example.cpp

$ ./a.out

To compile it with debug symbols so you can step through it in gdb, do this:

$ g++ -g -o debugtest example.cpp

$ gdb debugtest

You can now follow along with this tutorial.

For extra credit, try compiling this with clang++ instead!