gdb interview questions

Ask from any core C/C++ programmer or a white box tester, what tool they like to use for debugging the code? Most of them would vote for GDB debugger or the GNU debugger. So here we bring a GDB tutorial that lists essential GDB commands and some exclusive tips to boost your debugging skills. The full form of GDB is the GNU Project Debugger. And it’s the most important debugging tool for software geeks that work on UNIX and Linux-based systems.

Richard Stallman originally developed GDB debugger in 1986 while he was working on his GNU project. It’s an extraordinarily versatile and pliable tool. Mastering it would save you significant time in debugging the complex code issues. In this GDB tutorial, we’ll share all the basic to advance debugging tips that every C/C++ programmer can use.

Some of you may have several questions about GDB debugger at the back of your mind like “What is GDB or why is it used for or how to use GDB for debugging?”. But before we answer you, let’s see what Brian Kernighan has said about the debugging.

gdb And How To Debug C And C++ Code?

Interviews for Top Jobs at GDB Technologies

Front End Developer Interview

Python Developer Interview

5. GDB can be used for a) c language b) c++ language c) both c and c++ language d) none of the mentioned View Answer Answer: c Explanation: None.

10. To print the value of a variable while debugging with GDB, ______ command can be used. a) printf b) print c) show d) none of the mentioned View Answer Answer: b Explanation: None.

4. GDB stands for a) GNU debugger b) General debugging breakpoint c) General debugger d) None of the mentioned View Answer Answer: a Explanation: None.

3. In GDB, breakpoints can be set by the command a) break b) b c) both break and b d) none of the mentioned View Answer Answer: c Explanation: None.

1. For debugging with GDB, the file “sanfoundry” can be created with the command a) gcc -g -o sanfoundry sanfoundry.c b) gcc -g sanfoundry.c c) gdb sanfoundry d) none of the mentioned View Answer Answer: a Explanation: None.

10. Run the code by typing “run or r”.If you haven’t set any breakpoints, run command will simply execute the full program.

13. Below screenshot shows the values of variables from which it’s quite understandable the reason why we got a garbage value as output. At every execution of ./test we will be receiving different output.

Note: If an object that has automatic storage duration is not initialized explicitly, its value is indeterminate, where the indeterminate value is either an unspecified value or a trap representation.

If you want to put breakpoint at different lines, you can type “b line_number“.By default “list or l” display only first 10 lines.

3. Now compile the code. (here test.c).g flag means you can see the proper names of variables and functions in your stack frames, get line numbers and see the source as you step around in the executable.-std=C99 flag implies use standard C99 to compile the code.-o flag writes the build output to an output file.

GDB Tutorial: Learn Debugging Step by Step

A great debugging tool is one of the most critical assets of any programmer’s armory. It allows you to see what is going on “inside” another program at run-time. In this GDB tutorial, you’ll get to learn things like how to pause the code execution, inspect the state of any variable on the stack and so on. You’ll see how to use GDB for stepping through the source code and watch the changes to a variable.

And probably, you would like some other advantages of the GDB debugger that we’ve covered in this GDB tutorial. Also, we’ll lay out 100% practical ways that you can directly apply in your work environment.

So, better bookmark this GDB tutorial so that you can also refer it anytime while debugging the production code.

We’ll now start with the first steps in which you’ll prepare your program for the debugging.

FAQ

What is GDB tool and purpose?

What are the commands used in GDB?

What does breakpoint do in GDB?