Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is the documentation for a snapshot of the develop branch, built from commit e8d208b4bd.
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BOOST_OUTCOME_TRYV(expr)/BOOST_OUTCOME_TRY(expr)

Evaluate an expression which results in a type matching the following customisation points, continuing execution if successful, immediately returning try_operation_return_as(X) from the calling function if unsuccessful:

Default overloads for these customisation points are provided. See the recipe for supporting foreign input to BOOST_OUTCOME_TRY.

The difference between the BOOST_OUTCOME_TRYV(expr) and BOOST_OUTCOME_TRY(expr) editions is that the latter will set a variable if two or more macro arguments are present (see BOOST_OUTCOME_TRY(var, expr) ). The former requires the T to be void.

Hints are given to the compiler that the expression will be successful. If you expect failure, you should use BOOST_OUTCOME_TRYV_FAILURE_LIKELY(expr) instead.

An internal temporary to hold the value of the expression is created, which generally invokes a copy/move. If you wish to never copy/move, you can tell this macro to create the internal temporary as a reference instead.

Overridable: Not overridable.

Definition: Firstly the expression’s temporary is bound to a uniquely named, stack allocated, auto &&. If that reference’s bound object’s try_operation_has_value() is false, immediately execute return try_operation_return_as(propagated unique reference);, propagating the rvalue/lvalue/etc-ness of the original expression.

Header: <boost/outcome/try.hpp>

Last revised: February 12, 2021 at 20:25:43 UTC


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