alt Hacker NewsWhat operations could such frozen vector offer that std::vector does not? If there are none, it doesn't need a separate data structure.
Replies
einpoklum • yesterday at 11:16 AM
Oh, on the contrary, the separate structure is needed and useful because it offers _less_, not more:
* APIs/function signatures explain more clearly what are the intended uses of the structure that's passed.
* More potential for compiler optimization
* Some potential for having these on the stack (if the compiler deduces the size already at compile-time)
* More convenient for static analysis
* No plethora of confusing constructors (including the infernal two-element ctors which can be misinterpreted super-easily)
etc.
The reason I'd want "frozen-size vector" is to replace pairs of data members of the form `T* foos; size_t foos_len;` without paying another 8 bytes to store a useless capacity that's never going to change.
But I don't think that makes such a container worth adding to the STL. So far, it hasn't even been worth writing in our own code. But that's the reason I've thought about writing it.