[stmt.return.coroutine] (original) (raw)

8 Statements [stmt]

8.7 Jump statements [stmt.jump]

8.7.5 The co_return statement [stmt.return.coroutine]

A co_return statement transfers control to the caller or resumer of a coroutine ([dcl.fct.def.coroutine]).

A coroutine shall not enclose a return statement ([stmt.return]).

[Note 1:

For this determination, it is irrelevant whether the return statement is enclosed by a discarded statement ([stmt.if]).

— _end note_]

A co_return statement is equivalent to:

{ S; goto final-suspend; }

where final-suspend is the exposition-only label defined in [dcl.fct.def.coroutine]and S is defined as follows:

• The expression S shall be a prvalue of type void.
• The expression p.return_void()shall be a prvalue of type void.

If a search for the name return_void in the scope of the promise type finds any declarations, flowing off the end of a coroutine's function-bodyis equivalent to a co_return with no operand; otherwise flowing off the end of a coroutine's function-bodyresults in undefined behavior.