tmp/tmp4tahb0x7/{from.md → to.md}
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| 1 |
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### Function templates `bind_front` and `bind_back` <a id="func.bind.partial">[[func.bind.partial]]</a>
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``` cpp
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template<class F, class... Args>
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constexpr unspecified bind_front(F&& f, Args&&... args);
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template<class F, class... Args>
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constexpr unspecified bind_back(F&& f, Args&&... args);
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```
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Within this subclause:
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- `g` is a value of the result of a `bind_front` or `bind_back`
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invocation,
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- `FD` is the type `decay_t<F>`,
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- `fd` is the target object of `g` [[func.def]] of type `FD`,
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direct-non-list-initialized with `std::forward<F>(f)`,
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- `BoundArgs` is a pack that denotes `decay_t<Args>...`,
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- `bound_args` is a pack of bound argument entities of `g` [[func.def]]
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of types `BoundArgs...`, direct-non-list-initialized with
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`std::forward<Args>(args)...`, respectively, and
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- `call_args` is an argument pack used in a function call
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expression [[expr.call]] of `g`.
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*Mandates:*
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``` cpp
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is_constructible_v<FD, F> &&
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is_move_constructible_v<FD> &&
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(is_constructible_v<BoundArgs, Args> && ...) &&
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(is_move_constructible_v<BoundArgs> && ...)
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```
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is `true`.
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*Preconditions:* `FD` meets the *Cpp17MoveConstructible* requirements.
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For each `Tᵢ` in `BoundArgs`, if `Tᵢ` is an object type, `Tᵢ` meets the
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*Cpp17MoveConstructible* requirements.
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*Returns:* A perfect forwarding call
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wrapper [[term.perfect.forwarding.call.wrapper]] `g` with call pattern:
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- `invoke(fd, bound_args..., call_args...)` for a `bind_front`
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invocation, or
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- `invoke(fd, call_args..., bound_args...)` for a `bind_back`
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invocation.
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*Throws:* Any exception thrown by the initialization of the state
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entities of `g` [[func.def]].
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