GDBUserspaceDebuggingGuide

Comprehensive guide and resources for debugging userspace code using GDB. Dive deep into hands-on examples, best practices, and troubleshooting techniques. Perfect for beginners and seasoned developers looking to enhance their debugging skills in userspace environments

GDB Guide 🐞

What is GDB? 🤔

GDB stands for GNU DeBugger. It assists in debugging the binary object files created during the compilation process.

When a program crashes, especially during segmentation faults, GDB can be invaluable. It provides a window into the behavior of your program, allowing you to:

🔍 Step through a program line by line.
📍 Set breakpoints that halt your program.
🛑 Make your program stop under specific conditions.
📊 Display current variable values.
🔬 Examine the contents of any frame on the call stack.

Languages Supported by GDB 🌐

GDB supports a range of languages, including but not limited to:

Ada
Assembly
C
C++
D
Fortran
Go
Objective-C
OpenCL
Modula-2
Pascal
Rust

Installing GDB 💾

To install GDB, you can use the package manager on Debian-based systems:

$ sudo apt-get install gdb
$ gdb --version

Questions 🤓

Q1: What is the primary purpose of GDB?

A: GDB, the GNU DeBugger, is primarily used to debug binary object files created during the compilation process. It's invaluable for understanding program behavior, especially during crashes like segmentation faults.

Q2: Name some key functionalities provided by GDB?

A: GDB allows developers to step through programs line by line, set breakpoints, halt programs under specific conditions, display the current values of variables, and examine any frame on the call stack.

Q3: Which command is used to check the version of GDB?

A: The command to check the version of GDB is gdb --version.

Q4: Can GDB be used for languages other than C and C++?

A: Yes, GDB supports a variety of languages including Ada, Assembly, D, Fortran, Go, Objective-C, OpenCL, Modula-2, Pascal, and Rust, among others.

GDB Interview Questions and Answers 📖

Q5: For debugging with GDB, the file “source_code” can be created with the command:

A: a) gcc -g -o source_code source_code.c

Q6: For debugging with GDB, the compiled program can be run by the command:

A: a) run

Q7: In GDB, breakpoints can be set by the command:

A: c) both break and b

Q8: GDB stands for:

A: a) GNU debugger

Q9: GDB can be used for:

A: c) both c and c++ language

Q10: The command “gdb source_code”:

A: a) will start debugging for the file “source_code” if the file is compiled with -g option with GCC

Q11: In debugging with GDB, break points can be set to:

A: c) both any line and function

Q12: In GDB debugging, we can proceed to the next breakpoint with command:

A: b) continue

Q13: At the time of debugging with GDB, if we just press ENTER:

A: a) GDB will repeat the same command you just gave it

Q14: To print the value of a variable while debugging with GDB, which command can be used?

A: b) print

Q15: Which GDB command prints the value of a variable in hex?

A: a) print/x

Q16: Which GDB command interrupts the program whenever the value of a variable is modified and prints the value old and new values of the variable?

A: a) watch

Q17: Which GDB command produces a stack trace of the function calls that lead to a segmentation fault?

A: b) backtrace

Q18: The specific break point can be deleted by which command in GDB?

A: a) delete

Q19: The “step” command of GDB:

A: c) executes the current line of the program & stops the next statement to be executed

Q20: GDB can be used:

A: d) all of the mentioned

Q21: Which GDB command can be used to put a breakpoint at the beginning of the program?

A: a) b main

Q22: To put the breakpoint at the current line, which command can be used?

A: c) both b and break

Q23: We can list all the breakpoints in GDB by the command:

A: a) info break

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