QScopeGuard 类

template <typename F> class QScopeGuard

提供用于在作用域结束时调用函数的作用域守卫。 更多...

头：	#include <QScopeGuard>
qmake:	QT += core
Since:	Qt 5.12

该类在 Qt 5.12 引入。

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公共函数

	QScopeGuard (const F & f )
	QScopeGuard (F && f )
void	dismiss ()

相关非成员

QScopeGuard<typename std::decay<F>::type>

qScopeGuard (F && f )

详细描述

QScopeGuard<F> is a class of which the sole purpose is to run the function f in its destructor. This is useful for guaranteeing your cleanup code is executed, whether the function is exited normally, exited early by a return statement, or exited by an exception.

注意： Exceptions are not supported. The callable shouldn't throw when executed, copied or moved.

另请参阅 QScopedValueRollback .

成员函数文档编制

QScopeGuard:: QScopeGuard ( F && f )

QScopeGuard:: QScopeGuard (const F & f )

Create a scope guard that will execute f at the end of the scope.

若 F is a lambda, its type cannot be written. In that case you need to either rely on class template argument deduction (C++17 feature) and leave the template parameter out completely or use the helper function qScopeGuard () instead of this constructor.

该函数在 Qt 5.15 引入。

void QScopeGuard:: dismiss ()

Disarms the scope guard, so that the function F will not be called at the end of the scope.

相关非成员

template <typename F> QScopeGuard < typename std::decay < F > ::type > qScopeGuard ( F && f )

The qScopeGuard function can be used to call a function at the end of the scope.

Create a scope guard that will execute f at the end of the scope.

This helper function is provided so that you can easily construct a QScopeGuard without having to name the template parameter for the type of the callable. If F is a lambda then you cannot write its type and relying on this helper or class template argument deduction is necessary.

Example usage is as follows:

void myComplexCodeWithMultipleReturnPoints(int v)
{
    // The lambda will be executed right before your function returns
    auto cleanup = qScopeGuard([] { code you want executed goes HERE; });
    if (v == -1)
        return;
    int v2 = code_that_might_throw_exceptions();
    if (v2 == -1)
        return;
    (...)
}
					

内容

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• 详细描述