Lab 8
Debugging Code with GDB
Answer Sheet
Name: _________________________
Lab Section: ____________________
Complete this answer sheet using the instructions given in the lab.
Turn in a hard copy of your completed sheet to your TA by the beginning
of your lab next week.
Compiling
1) Write the size (in bytes) of the executable ___________ (Note: The size
in bytes is the number immediately before the date in the output from
the ls -l command)
2) Now, recompile using the -g command line option and write the size in bytes of the new executable: _______________
Starting GDB
3) Copy the first
line that is printed when you run gdb:
___________________________________
4) Now, copy the portion in the quotes on the line that states "This GDB
was configured as." For instance, in the example above, you would copy
i686-linux-gnu: _________________________________
Getting Help
5) Write the
number of topics/classes: _____________
6) Now, type "help break" to get specific information:
Write the first line printed after executing the command here: _________________________________________
Running a Program
7) Try it now. What happened? ___________________________________________
8) Try the run command again, this time adding the command line
argument "1." What happened this time? ___________________________
Setting Breakpoints
9) At what line number does execution pause? _________________
A Brief Digression
10) Write what you see as a result: ________________________
Stepping Through Code
11) On what line does the program execution pause? _______________
12) Use the print statement mentioned above to print the
current value of sum. What is its current value? _______________
13) Now, use the step command step over the current line. At what line does the execution pause? ___________________
14) Print the value of sum again. What is its value now? _______________
15) Continue stepping through the program until the following line is reached:
sum += sum + i;
16) Print the value of sum: ________________
Displaying Variables
17) What is the value of the variable 'i' at
this point? ____________________
18) Once you see what the bug is, describe it
below: