gdb_demo

GDB is a debbuger tool that supports a number of programming languages, including C++.

This project contains a handful of examples to illustrate some of its capabilities.

Official documentation: https://www.gnu.org/software/gdb/documentation/

Usage

Synopsys

run <1|2|3>

Description

Execute the example specified via argument (3 examples available, accepted values 1, 2 or 3). Note that the code has some known bugs (commented in the code) to demostrate the capabilities of GDB.

Commands

 b (break):      https://sourceware.org/gdb/current/onlinedocs/gdb/Set-Breaks.html#index-b-_0028break_0029
 c (continue):   https://sourceware.org/gdb/current/onlinedocs/gdb/Continuing-and-Stepping.html#index-c-_0028continue_0029
 f (frame):      https://sourceware.org/gdb/current/onlinedocs/gdb/Selection.html#index-f-_0028frame_0029
 i (info):       https://sourceware.org/gdb/current/onlinedocs/gdb/Help.html#index-i-_0028info_0029 
 l (list):       https://sourceware.org/gdb/current/onlinedocs/gdb/List.html#index-l-_0028list_0029
 n (next):       https://sourceware.org/gdb/current/onlinedocs/gdb/Continuing-and-Stepping.html#index-n-_0028next_0029
 p (print):      https://sourceware.org/gdb/current/onlinedocs/gdb/Data.html#index-print
 s (step):       https://sourceware.org/gdb/current/onlinedocs/gdb/Continuing-and-Stepping.html#index-s-_0028step_0029
 bt (backtrace): https://sourceware.org/gdb/current/onlinedocs/gdb/Backtrace.html#index-bt-_0028backtrace_0029
 C-X 1 (TUI 1):  https://sourceware.org/gdb/current/onlinedocs/gdb/TUI-Keys.html#index-C_002dx-1
 C-X 2 (TUI 2):  https://sourceware.org/gdb/current/onlinedocs/gdb/TUI-Keys.html#index-C_002dx-2
 record:         https://sourceware.org/gdb/current/onlinedocs/gdb/Process-Record-and-Replay.html#index-record
 stop:           https://sourceware.org/gdb/current/onlinedocs/gdb/Hooks.html#index-stop_002c-a-pseudo_002dcommand

Additional commands can be found here:

List of all available commands: https://sourceware.org/gdb/current/onlinedocs/gdb/Command-and-Variable-Index.html#Command-and-Variable-Index

List of reverse commands: https://www.gnu.org/software/gdb/news/reversible.html

Examples

Example 1

Give 2 integer numbers A and B, the following 5 operations are performed:

  sum  = A + B
  sub  = A - B
  div  = A / B
  prod = A * B
  total = sum + sub + div + prod

This example contains two error:

• sum is printed on screen when sub is expected (demostrate how to look for bugs)
• division by zero is not being handled (demostrate how GDB handles critical exceptions)

Example 2

Same as example 1, but using a lambda instead of a function. This allows to observe how these two approaches (functions vs labda) can be debugged using GDB. The main difference is that, given the nature of the labda functions, breakpoints cannot be added givein their name.

Example 3

Same as examples 1 and 2, but the product of A * B is calculated recursively so we add A to a counter B times. This function has a bug when calculating the product (need to return 0 on the base case). Also note that the two bugs from the previous examples have been fixed here.

Jose Miguel Armijo Fidalgo https://www.linkedin.com/in/jmarmijo/