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 master branch, built from commit c7eba69776.
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Function template public_function

boost::contract::public_function — Program contracts for static public functions.

Synopsis

// In header: <boost/contract/public_function.hpp>


template<typename Class> 
  specify_precondition_old_postcondition_except public_function();

Description

This is used to specify preconditions, postconditions, exception guarantees, old value copies at body, and check static class invariants for static public functions:

class u {
    friend class boost::contract::access;

    static void static_invariant() { // Optional (as for non-static).
        BOOST_CONTRACT_ASSERT(...);
        ...
    }

public:
    static void f(...) {
        boost::contract::old_ptr<old_type> old_var;
        boost::contract::check c = boost::contract::public_function<u>()
            .precondition([&] { // Optional.
                BOOST_CONTRACT_ASSERT(...);
                ...
            })
            .old([&] { // Optional.
                old_var = BOOST_CONTRACT_OLDOF(old_expr);
                ...
            })
            .postcondition([&] { // Optional.
                BOOST_CONTRACT_ASSERT(...);
                ...
            })
            .except([&] { // Optional.
                BOOST_CONTRACT_ASSERT(...);
                ...
            })
        ;

        ... // Function body.
    }
    
    ...
};

For optimization, this can be omitted for static public functions that do not have preconditions, postconditions and exception guarantees, within classes that have no static invariants.

See Also:

Static Public Functions

Template Parameters:

Class

The type of the class containing the static public function declaring the contract. This template parameter must be explicitly specified for static public functions (because they have no object this so there is no function argument from which this type template parameter can be automatically deduced by C++).

Returns:

The result of this function must be assigned to a variable of type boost::contract::check declared explicitly (i.e., without using C++11 auto declarations) and locally just before the code of the static public function body (otherwise this library will generate a run-time error, see BOOST_CONTRACT_ON_MISSING_CHECK_DECL).


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