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The jss::update_guard<> class template provides scoped access to the wrapped object inside an instance of the jss::synchronized_value class template. The type of object being accessed is specified by template parameter T. The internal mutex of the jss::synchronized_value<> instance is locked in the jss::update_guard<> constructor and unlocked in the destructor. This provides a simple means of locking the mutex for a block of code so that multiple operations can be performed on the wrapped object whilst ensuring that the mutex is unlocked when the block is left, whether that is by running off the end, by the use of a control flow statement such as break or return, or by throwing an exception.

Access to the wrapped object can be obtained through the use of the pointer dereference operators on the jss::update_guard<> instance.

Instances of jss::update_guard<> are neither MoveConstructible, CopyConstructible or CopyAssignable.

template <class T>
class update_guard
    explicit update_guard(jss::synchronized_value<T>& sv);

    T& operator*();
    T* operator->();

    update_guard(update_guard const& ) = delete;
    update_guard& operator=(update_guard const& ) = delete;

#include <jss/synchronized_value.hpp>

See Also