You (probably) don't need to learn C
Claims that modern programmers “probably don’t need to learn C” prompt debate over how much low-level knowledge is necessary to be effective. Many argue that C (or a similar systems language) is invaluable for understanding memory, performance, and the abstractions underlying higher-level languages, while others counter that real hardware behavior is now far below C’s model and most careers succeed without it. The exchange highlights trade-offs between depth and breadth: limited learning time, the complexity and pitfalls of C itself, and the practical benefits of being able to read or reason about the large body of existing C-based systems.
Scope: Do You “Need” to Learn C?
- Many agree you don’t need C to be a productive or even “great” programmer; plenty of modern work is done purely in higher-level languages.
- Others argue for being “well‑rounded”: knowing at least one systems language (often C, C++, Rust, Zig) gives a broader understanding of software.
- Some push back on rhetoric that everyone must learn C; others say time is limited and C may not give the benefits people think it does.
C and “How Computers Really Work”
- One side: C no longer reflects modern hardware well (pipelines, caches, branch prediction, multicore, virtual memory, microcode), so it doesn’t truly show “how computers really work.”
- Counterpoint: C still maps more directly to hardware/OS behavior than Python/JS and is “as low as user space goes” short of assembly; learning it gives meaningful intuition about memory, layout, and performance.
- Several note that no language really exposes all modern hardware details; even assembly hides some layers.
Memory Model, Pointers, and Undefined Behavior
- Long debate over whether C encourages thinking of memory as “one big array of bytes.”
- Some say: that’s only an abstract model; OS, MMU, virtual memory, and segmentation break that intuition.
- Others: within objects/arrays, C does guarantee virtual contiguity; physical layout is irrelevant to the abstract machine.
- Thread distinguishes:
- C’s concurrency memory model (stdatomic) vs. informal “how memory looks.”
- Implementation‑defined behavior (e.g., int↔pointer casts) vs. undefined behavior (e.g., out‑of‑bounds access, some pointer lifetime issues).
- Pointers are described as conceptually simple but practically treacherous: major source of bugs, UB, and security issues.
Practical Reasons to Learn C
- Reading and modifying large existing C codebases (kernels, databases, libraries, embedded code).
- Understanding low-level constructs used by higher-level languages: allocation, stacks/heaps, structs, vtables, reference counting, FFI boundaries.
- Communicating with colleagues who “think in C” or in systems abstractions.
Alternatives and Pedagogical Views
- Some suggest courses like building a VM/compiler or nand2tetris as better pathways to understanding systems than “learn C.”
- Others like C as a teaching tool because you must implement data structures (maps, vectors, strings) yourself, revealing costs hidden in higher-level languages.
- Tooling pain (Make/CMake, multi-platform builds) is cited as a downside versus integrated toolchains like Rust/Go.