Debugging

assert()

Takes a Boolean expression as a parameter and terminates the program if it is false, but continues otherwise.

debugger

a program that runs your program within a controlled
environment

gdb

GNU Debugger

How do you start gdb

gdb [program name]

What is the flag for a simple terminal gdb interface

-tui

What is the command to run the program in gdb

run [args] (if any)

What is the command for looking at regions of code

list (l)

How do you set a breakpoint on a specific line

break (b) [line]

How do you set a breakpoint at a certain function

break (b) [function | line]

How do you delete a breakpoint

delete [breakpoint number]

conditional breakpoint

a point where you want the debugger only if the
condition holds

How do you create a conditional breakpoint

cond [breakpoint_number] (expr)
or
b [line | function] if (expr)

How do you see all of your breakpoints

info breakpoints

How can you save breakpoints in a file for later use

save breakpoints [textfile name]

How can you load saved breakpoints

source [textfile name]

Watchpoint/data breakpoint

stop execution whenever the value of a variable changes, without a particular place where it happens.

where command

gives you a stack and the specific line number you are on. Tells you where you are in the program

up and down commands

moves up and down the stack and see different variables

How do you print variables in gdb

print /[format] variable

What are the formats for binary, hex, int, unsigned int, string, octal, float, address, and instruction, respectively

t(binary), x(hex), d(int), u(unsigned int), s(string), o(octal), f(float), a(address), i(instruction)

x command

examines a memory region

How do you call the x command

x [/<num><format><size>] address

What are the applicable sizes for the x command

b(byte), h(halfword), w(word), g(giant, 8 bytes)

next(n)

goes to the next line in the program

step(s)

goes to the next line in the program, but steps into a function if there is one.

continue(c)

runs the program until it terminates or hits another breakpoint

finish(f)

continues until it reaches a return statement