Evaluate an expression which results in a type matching the ValueOrError<T, E> concept, assigning T to a variable called var if successful, immediately returning try_operation_return_as(expr) from the calling function if unsuccessful.

Overridable: Not overridable.

Definition: See BOOST_OUTCOME_TRYV(expr) for most of the mechanics.

If successful, an auto &&var is initialised to the expression result’s .assume_value() if available, else to its .value(). This binds a reference possibly to the T stored inside the bound result of the expression, but possibly also to a temporary emitted from the value observer function.

Header: <boost/outcome/try.hpp>