Lab 09 -- C Programming - Files, GDB, Valgrind, Linked lists

This page gives an overview of the lecture and the lab session on Sep 25, 2025.

Short lecture summary

• Dynamic memory allocation for two dimensional arrays and freeing memory.

• File handling. Opening, reading, writing, closing files.

• Buffering of stdout and the need for use of debugging tools - GDB. Demo for GDB usage. GDB reference card - for a quick summary of options.

• Detecting memory leaks using valgrind. Demo for valgrind usage. Valgrind reference card - for a quick usage summary.

• Singly and Doubly linked lists. Head of a linked list. Insert and delete operations.

Readings

1. Peter Jay’s GNU Debugger write-up

   An excellent and in-depth write up on how to get the most out of GDB.

   Read Chapter

   • Chapter 1: Introduction
   • Chapter 2: Memory layout and the Stack
   • Interlude: Debugging With Your Brain
   • Chapter 3: Initialization, Listing, And Running
   • Chapter 4: Breakpoints and Watchpoints

2. C Programming A Modern Approach (2nd Ed) by K. N. King (Online version)

   

   Read chapters

   • Chapter 19. Program Design
   • Chapter 22. Input/Output

3. Dive Into Systems by Suzanne J. Matthews, Tia Newhall, Kevin C. Webb (Online version)

   

   Read chapters

   • Chapter 3. C Debugging tools
   • Chapter 3.3. Debugging memory with Valgrind

4. Using Valgrind and interpreting the error messages, see this write-up.

Practise

1. Work out the problems in this tutorial on GDB.

2. A tutorial on valgrind usage with an explanation of its output.

Additional readings

• Valgrind technical documentation

• Guide to debugging with Valgrind.