Thoughts on C++ 26

Sutter's video

 The other day I watched Sutter's YouTube video about 3 cool things in C++ 26:

1. Make C++ safer by replacing undefined behavior (UB) with erroneous behavior (EB)
2. Reflection
3. Yet another syntax for async

Safe C++ 

Sutter mentions two aspects:

• uninitialized local variables will be mangled. The compiler may inject code to check if uninitialized variables are accessed.
• hardening of STL; most notably operator[] 

According to studies the overhead is minimal (0.3%). This number is debatable: they can never know what applications are out there. In the past experience we had bad experience with VS 2008 who turned on safe iterators in release builds. They killed all compiler optimizations right away when used.

I question also the first bullet: why not make it simpler and state that every variable will be default or zero initialized. There is no EB or UB necessary; or no hidden code injected by the compiler.

Some of the hardened STL functions are unnecessary. There are already 'at()' functions which bounds check. A safety profile could warn for use of operator[].

Reflection

Nice that reflection is added but I wonder if the C++ committee has the right priorities. The standard library even lacks a standard JSON or XML library which would be an ideal candidate for automatic serialization through reflection.

Async

They added a new superfluous new syntax. So much for consistency.

 Conclusion

Memory safety is an issue but I believe more in safety profiles than changing the language. Reflection is nice but what C++ lacks most is standard libraries; not major language changes.