What is std::execution (C++26)?

Question

Accepted Answer

**Senders/Receivers** — structured concurrency model.

```cpp
#include <execution>

using namespace std::execution;

auto work = just(42)
    | then([](int x) { return x * 2; })
    | then([](int x) { return std::to_string(x); });

sync_wait(work); // blocks until done
```

**Key concepts:**
- **Sender**: produces values
- **Receiver**: consumes values
- **Scheduler**: controls where work runs
- **Operation state**: owns the work

**Schedulers:**
```cpp
auto pool = thread_pool(4);
auto sched = pool.get_scheduler();

auto work = just(42)
    | on(sched)
    | then([](int x) { return x * 2; });
```

**Benefits:**
- Structured concurrency
- Composable async operations
- Exception propagation

C++: What is std::execution (C++26)?