构造函数抛出异常时释放内存 [英] Free memory when constructor throw exeception

问题描述

你好，



如果构造函数在堆上分配一些内存（使用new）之后抛出任何execpetion那么我们如何释放分配的内存。



我尝试了什么：



如果构造函数在分配了一些内存后抛出任何execpetion （在堆上使用new）然后我们如何释放分配的内存。

Hello,

If constructor is throwing any execpetion after allocating some memory (using new) on heap then how can we free that allocated memory.

What I have tried:

If constructor is throwing any execpetion after allocating some memory (using new) on heap then how can we free that allocated memory.

推荐答案

只需处理catch all块内的异常并重新抛出异常：

Just handle the exceptions inside a catch all block and rethrow the exception:

MyClass::MyClass() :
    member1(NULL)
    ,member2(NULL)
{
    // Initialise all pointers to memory to be allocated with NULL here or
    // as shown above.
    // Then delete can be safely called for them.
    //member1 = NULL;
    //member2 = NULL;
    try
    {
        // Memory allocation
        member1 = new Member1Type;
        member2 = new Member2Type;
    }
    catch (...)
    {
        // Cleanup here deleting all allocated memory
        delete member2;
        delete member1;

        // Re-throw the exception so that it can be handled again
        throw();
    }
}

因为释放内存通常也是在析构函数中完成的，所以编写一个可以从中调用的清理函数是很常见的。析构函数和上面的 catch 块。

另请参见：如果我的构造函数可能抛出异常，我应该如何处理资源？ [ ^ ]

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