What if a noexcept function throws?

The program typically calls `std::terminate`—treat noexcept as a hard contract.

Why noexcept move for containers?

Some operations require strong exception guarantees; if move might throw, implementations may fall back to copying elements.

`noexcept(noexcept(expr))` propagates nothrow-ness from members—common in wrappers.

2026년 3월 12일 · 10분 읽기 · 수정 2026년 3월 12일 Intermediate Tutorial

Use noexcept to document non-throwing operations and unlock vector reallocation and other optimizations safely.

noexcept states that a function does not throw exceptions. If it does anyway, std::terminate is invoked (typically).

void f() noexcept;
void g() noexcept(true);   // same as noexcept
void h() noexcept(false);  // may throw

Enables optimizations (less unwind machinery assumed).
Move operations on std::vector elements: if move is noexcept, reallocation can move; otherwise copies may be used for exception safety.

template<typename T>
void swap(T& a, T& b) noexcept(noexcept(T(std::move(a)))) {
    // ...
}

Destructors are implicitly noexcept unless a base or member destructor is noexcept(false) (rules tightened over standards—verify for your version).

static_assert(noexcept(f()));

C++, noexcept, exceptions, optimization, move constructor