C

C is an imperative compiled programming language. It’s an important starting language in computer engineering since:

• The language interacts so closely with hardware.
• It introduces concepts in the context of memory.
• It requires us to implement many functions by hand.

It lacks things like objects and classes, but it does introduce finer control of memory and hardware components. Not to be confused with C++ — which is not a superset of C but closely related.

C versions are expressed by the year of release. The most common versions are C89, C99, and C11. The two dominant C compilers are GCC and Clang.

Language features

Basics

• Data types
  • Floating-point number (float, double)
  • Composite types
    • struct (struct)
    • Union type (union)
  • typedef
• Qualifiers
  • Type qualifier
    • const (const)
    • volatile (volatile)
    • restrict (restrict)
    • Atomics (Atomic_)
  • Storage-class specifier (static)
  • Inline function (inline)
  • Attribute
• Memory
  • Pointer
  • Heap allocation
  • Segmentation fault
• Preprocessor
  • Header file
  • Preprocessor macro

Advanced

• Undefined behaviour

Libraries

• stdio.h
• stdlib.h
• string.h
• gmp.h

Tools

• Compilers
  • GCC
  • Clang
• Debuggers
  • GDB
  • LLDB
  • Valgrind
• Build tools
  • Make
  • CMake
  • Meson

Internals

C runtime startup — Systeminit function before main

Development environment

An opinionated set-up:

• Compiler — Clang
• Linter/language server — clangd
• IDE — CLion or VSCode

Quick install

choco install llvm
choco install vscode

Resources

• General reference
  • cppreference.com
  • Beej’s Guide to C Programming (Library Reference)
• For an introduction to the language:
  • Beej’s Guide to C Programming, by Brian Hall (2023)
  • Modern C, by Jens Gustedt (2021)
• Guiding thoughts about the language
  • C is Not a Low-level Language, by David Chisnall

Courses

• APS105 — Computer Fundamentals, for introductory C
• ECE243 — Computer Organization, for embedded C
• ECE344 — Operating Systems, for systems C