C/C++ Best Practices

C/C++ Best Practices

C gives you full control; C++ gives you abstractions to manage that control safely. In both, every allocation must have an owner and every pointer must have a valid target.

Memory Management

• C: pair every malloc with free. Use a single owner convention -- whoever allocates is responsible for freeing.
• C++: RAII everywhere. Acquire resources in constructors, release in destructors. Never call new/delete directly in application code.
• Smart pointers (C++): std::unique_ptr for sole ownership, std::shared_ptr only when ownership is genuinely shared. Avoid std::shared_ptr as a default.
• Prefer stack allocation. Heap-allocate only when lifetime must exceed the current scope or size is unknown at compile time.

Const Correctness

• Mark parameters const unless mutation is intended: void process(const std::string& input).
• Mark member functions const when they do not modify state.
• In C, use const pointers: const char* str (pointer to const data) vs char* const ptr (const pointer).

Tooling

Tool	Purpose
CMake	Build system -- use target_* commands, avoid global settings
clang-tidy	Static analysis -- enable modernize-*, bugprone-*, cppcoreguidelines-*
AddressSanitizer	Runtime detection of buffer overflows, use-after-free (-fsanitize=address)
Valgrind / memcheck	Memory leak detection, uninitialised reads
clang-format	Code formatting -- enforce in CI

Testing

• Google Test or Catch2 for C++ unit tests. Integrate with CTest via CMake.
• Run tests under ASan and UBSan in CI to catch memory and undefined behavior bugs early.

Common Pitfalls

Pitfall	Fix
Buffer overflow (out-of-bounds write)	Use std::vector/std::array (C++), bounds-check in C, enable ASan
Dangling pointer / use-after-free	RAII + smart pointers; never return pointers to locals
Undefined behavior (signed overflow, null deref)	Enable -fsanitize=undefined, test with UBSan
Memory leaks	Valgrind in CI, RAII in C++, cleanup functions in C
Missing virtual destructor (C++)	Always declare virtual ~Base() = default for polymorphic base classes
Raw new/delete in modern C++	Use std::make_unique / std::make_shared exclusively

Attribution

Original -- Datatide, MIT licensed.