Finally in C++

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南旧 2020-12-28 08:33

Is this a good way to implement a Finally-like behavior in standard C++? (Without special pointers)

class Exception : public Exception
    { public: virtual


      
      
        
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                   悲&欢浪女
                                             
                
                
                (楼主)
            
              
              
                2020-12-28 09:27
              

            
            
                        
If for some strange reason you don't have access to the standard libraries, then it's very easy to implement as much as you need of a smart pointer type to handle the resource. It may look a little verbose, but it's less code than those nested try/catch blocks, and you only have to define this template once ever, instead of once per resource that needs management:

template
struct MyDeletable {
    explicit MyDeletable(T *ptr) : ptr_(ptr) { }
    ~MyDeleteable() { delete ptr_; }
private:
    T *ptr_;
    MyDeletable(const MyDeletable &);
    MyDeletable &operator=(const MyDeletable &);
};

void myfunction() {
    // it's generally recommended that these two be done on one line.
    // But it's possible to overdo that, and accidentally write
    // exception-unsafe code if there are multiple parameters involved.
    // So by all means make it a one-liner, but never forget that there are
    // two distinct steps, and the second one must be nothrow.
    Object *myObject = new Object();
    MyDeletable