std::generator (C++23)

One-Liner

A coroutine generator that lazily produces a sequence of values—replaces hand-written iterators, features zero heap allocation (customizable allocator), and reduces code volume by an order of magnitude.

Header

#include <generator>

Core API Cheat Sheet

Operation	Signature	Description
Generator Type	template<class T> class generator	Lazy value sequence, satisfies the view concept
Yield Value	co_yield expr;	Yields a value and suspends
Finish Generation	co_return;	Ends the generator
Iteration	generator::iterator	Input iterator, for range-for loops
Range Adaptation	Directly usable in ranges:: pipelines	Generator is a view, composable
Reference Type	generator<const T&>	Yield by reference (avoid copies)
Allocator	template<class T, class Alloc> class generator	Customizable coroutine frame allocator

Minimal Example

// Standard: C++23
#include <generator>
#include <iostream>

std::generator<int> fibonacci() {
    int a = 0, b = 1;
    while (true) {
        co_yield a;
        auto tmp = a;
        a = b;
        b = tmp + b;
    }
}

int main() {
    for (int v : fibonacci() | std::views::take(8)) {
        std::cout << v << " "; // 0 1 1 2 3 5 8 13
    }
}

Embedded Applicability: Moderate

• Lazy evaluation: Computes the next value only when needed, without pre-allocating memory for the entire sequence.
• Coroutine frames can use custom allocators, suitable for static memory pools.
• Replaces hand-written iterators and callback functions, significantly improving code readability.
• C++23 feature; compiler support is still ongoing (GCC 14+, Clang 17+, MSVC 19.34+).
• Generator lifetime management requires attention: accessing yielded values after the generator is destroyed is undefined behavior.

Compiler Support

GCC	Clang	MSVC
14	17	19.34

See Also

• cppreference: std::generator

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部分内容参考自 cppreference.com，采用 CC-BY-SA 4.0 许可