tmp/tmpvu9t18jo/{from.md → to.md}
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| 1 |
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### Fallthrough attribute <a id="dcl.attr.fallthrough">[[dcl.attr.fallthrough]]</a>
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The *attribute-token* `fallthrough` may be applied to a null statement (
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[[stmt.expr]]); such a statement is a fallthrough statement. The
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*attribute-token* `fallthrough` shall appear at most once in each
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*attribute-list* and no *attribute-argument-clause* shall be present. A
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fallthrough statement may only appear within an enclosing `switch`
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statement ([[stmt.switch]]). The next statement that would be executed
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after a fallthrough statement shall be a labeled statement whose label
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is a case label or default label for the same `switch` statement. The
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program is ill-formed if there is no such statement.
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[*Note 1*: The use of a fallthrough statement is intended to suppress a
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warning that an implementation might otherwise issue for a case or
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default label that is reachable from another case or default label along
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some path of execution. Implementations are encouraged to issue a
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warning if a fallthrough statement is not dynamically
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reachable. — *end note*]
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[*Example 1*:
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``` cpp
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void f(int n) {
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void g(), h(), i();
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switch (n) {
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case 1:
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case 2:
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g();
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[[fallthrough]];
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case 3: // warning on fallthrough discouraged
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h();
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case 4: // implementation may warn on fallthrough
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i();
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[[fallthrough]]; // ill-formed
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}
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}
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```
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— *end example*]
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