Using LLDB

Written by haloboy777 on 2023-11-16T20:45:49

Using LLDB to debug C++ code

Using lldb is quite pleasant. It is a command line debugger that is available on MacOS and Linux. It is similar to gdb and I heared gdb is nicer. But on macos it's available by default so we'll use this only. It is also possible to use lldb on Windows but I have not tried it.


On MacOS, lldb is installed by default. On Linux, you can install it using the following command:

sudo apt install lldb


To debug a program, you can use the following command:

lldb <program>

This will open the lldb prompt. You can then use the following commands to debug your program:

There is also a gui mode that can be used by running the following command:

lldb <program>
b <function_name>


Let's say we have the following program:

#include <iostream>

int main() {
    int a = 1;
    int b = 2;
    int c = a + b;
    std::cout << c << std::endl;
    return 0;

Then make sure you complie it with the -g flag:

g++ -std=c++11 -g main.cpp

We can debug it using the following commands:

lldb a.out
b 5

This will set a breakpoint at line 5 and run the program. The program will stop at line 5 and we can use the following commands to inspect the variables: