qswap.qdoc

Go to the documentation of this file.

// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
/*!
    \fn template <typename T> void qSwap(T &lhs, T &rhs)
    \relates <QtSwap>
 
    Exchanges the values of variables \a lhs and \a rhs,
    taking type-specific \c{swap()} overloads into account.
 
    This function is Qt's version of
    \l{https://www.boost.org/doc/libs/release/libs/core/doc/html/core/swap.html}{\c{boost::swap()}},
    and is equivalent to
    \code
    using std::swap;   // bring std::swap into scope (for built-in types)
    swap(lhs, rhs);    // unqualified call (picks up type-specific overloads
                       // via Argument-Dependent Lookup, or falls back to std::swap)
    \endcode
 
    Use this function primarily in generic code, where you would traditionally
    have written the above two lines, because you don't know anything about \c{T}.
 
    If you already know what \c{T} is, then use one of the following options, in
    order of preference:
 
    \list
    \li \c{lhs.swap(rhs);} if such a member-swap exists
    \li \c{std::swap(lhs, rhs);} if no type-specific \c{swap()} exists
    \endlist
 
    See
    \l{https://www.boost.org/doc/libs/release/libs/core/doc/html/core/swap.html}{\c{boost::swap()} on boost.org}
    for more details.
 
    See also
    \l{https://en.cppreference.com/w/cpp/algorithm/swap}{\c{std::swap} on cppreference.com},
    \l{https://en.cppreference.com/w/cpp/named_req/Swappable}{\c{Swappable} on cppreference.com}.
*/