Debuggers

A debugger is a computer program that is used to debug (and sometimes test or optimize) other programs.

These have been around forever (or at least 45 years) and are often built into fancy "Integrated Development Environments".

Debuggers can de dived into simple "command line debuggers" (like gdb) and ones with fancier, graphical user interfaces.

In either case, the basics are pretty much the same.

GDB

GDB (Gnu Debugger) is a powerful tool that can be used to monitor your programs as they execute. It allows you to suspend execution on any line, or in response to criteria you specify. It allows you to display and change variables, and trace their status during execution

There are many other things GDB can do that are outside the scope of this introduction. Much more information can be found on the gdb manual page (man gdb), and many tutorials can be found with a simple web search, using gdb and tutorial as keywords.

We'll look at how to Compile your programs to take advantage of GDB

• Start and stop the debugger
• LIST your source code inside the debugger
• RUN your code inside the debugger
• Execute the NEXT line of code
• BREAK program execution at a given line number or function
• WATCH the changes of variables during execution

We'll also take a brief look at DDD, Gnu's "Data Display Debugger" -- a graphical front end for GDB and other command line debuggers.