gdb and ddd Tutorial

Compile with debug support
    gcc -g myprog.c -o myprog

Start ddd and load program
    ddd myprog

Load a program. (You can skip this step because we load the program in previous step)
     file myprog

 Breakpoints

Set a breakpoint at specific line (e.g. break at line 7 of myprog.c)

     break myprog.c:7

Set a breakpoint at when calling specific function (e.g break when myfunc is called)
     break myfunc

Set a conditional breakpoint (e.g. variable myvar <= 3)
     break myprog.c:7 if myvar <= 3

Show breakpoints
     info breakpoints

Ignore specific breakpoint (e.g. ignore breakpoint 1 for 100 times. You can get number from "show breakpoints")
      ignore 1 100

Delete a breakpoint (Delete breakpoint 1. You can get number from "show breakpoints")
     delete 1

Control

Set watchpoint. (Stop execution when program changes the specific variable)
      watch myvar

Continue running after it hit a breakpoint
     continue

Finish (Finish current function)
     finish

Step Over (Trace into a function)
     step

Next (Treat function as a normal statement)
     next

Run/Restart the program
     run

Variables

Print content of specific variable (e.g. print content of myvar)
     print myvar

Print in hexadecimal
     print/X myvar