C++26: A User-Friednly assert() macro
3 days ago
- #C++26
- #programming
- #assert macro
- The assert() macro in C++ validates runtime conditions and aborts the program if false.
- assert() is problematic because it is a lowercase macro that doesn't understand C++ syntax like templates or braces, causing compilation errors with certain assertions.
- P2264R7 proposes making assert a variadic macro using __VA_ARGS__ to fix these issues, allowing previously broken assertions to work without extra parentheses.
- The proposal prevents accidental misuse with the comma operator for diagnostics; instead, the && operator must be used for diagnostic messages.
- Improving assert remains valuable even with future contracts, as assert will continue to be used in codebases, and the change is backward compatible.
- The change is a small, incremental improvement that eliminates compilation surprises and makes C++ more user-friendly, though not yet widely available in compilers as of early 2026.