C23 Highlights in C
From the C cheat sheet · Modern C (C23) · verified Jul 2026
C23 Highlights
Keywords and features new to C23.
c
// Quick Reference
bool ok = true; // keywords (no <stdbool.h>)
int *p = nullptr; // typed null
constexpr int SIZE = 10; // compile-time constant
[[nodiscard]] int f(void);💡 C23 makes bool/true/false/static_assert keywords - no more <stdbool.h> or _ prefixes.
⚡ nullptr is a typed null; constexpr defines genuine compile-time constants.
📌 [[nodiscard]] warns when a function's return value is ignored (e.g. an error code).
🟢 Compile with -std=c23 (gcc 13+/clang 16+) to use these; check __STDC_VERSION__ >= 202311L.
c23modern