Lab 10 -- C Programming - Programming across files, Makefiles, Unit Testing

This page gives an overview of the lecture and the lab session on Oct 09, 2025.

Short lecture summary

• Programming in multiple files and folders. Compilation and Linking. Functions of a linker. Header files and macros (#ifndef, #endif). Creating libraries.

• Unit testing and need for unit testing. Demo for unit testing.

• Using makefile. Writing makefile rules. Encoding dependency among programs across files in determining the order of compilation.

• Using realloc() and using it to build python list as a library in C.

Readings

1. Make files not war. Detailed write-up on makefile discussing many features that were mentioned in the class.

2. Understanding make files by Aniket Bhattacharyea.

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

   

   Read chapter

   • Chapter 17.5. Make and makefiles

4. Note for new make users by Alexander Gromnitsky.

Practise

1. Work out the makefile tutorial and check the makefile cookbook. Covers many features which did not cover in the class.

2. Work out the simple makefile tutorial.

Additional readings

• Benefits of multi-file programming (stackexchange answer)

• On Multi-file projects by Beej.

• Unit testing seen in the class is simple and does not use any special frameworks. However, there are frameworks like cunit, check and munit that can make testing easier.

• Catastrophies from failure in writing test cases.

  • Software error at Knight Capital - lack of testing and version control led to $440 million loss. The company was eventually acquired by their rivals.
  • List of software bugs
  • Ariane 5
  • Mars Climate Orbitor
  • Therac 25