QScopedArrayPointer守着我的數據，但它仍然是泄漏

#include <QScopedArrayPointer> 
#include <QDebug> 
#include <stdexcept> 

class MyData{ 
public: 
    MyData() { 
    qDebug() << "Construct a data"; 
    } 

    ~MyData() { 
    qDebug() << "Delete a data"; 
    } 

private: 
    float internal_data_; 
}; 

class MyClass{ 
    QScopedArrayPointer<MyData> data_; 
public: 
    MyClass(){ 
    data_.reset(new MyData[10]); 

    throw std::runtime_error("Shit happens"); 
    } 
}; 

int main(int argc, char *argv[]) 
{ 
    MyClass a_class; 

    return 1; 
}

運行這個程序將會輸出：QScopedArrayPointer守着我的數據，但它仍然是泄漏

Construct a data 
Construct a data 
Construct a data 
Construct a data 
Construct a data 
Construct a data 
Construct a data 
Construct a data 
Construct a data 
Construct a data 
terminate called after throwing an instance of 'std::runtime_error' 
    what(): Shit happens 
The program has unexpectedly finished.

權runtime_error之前，變量data_中已經完全建立。爲什麼data_析構函數沒有被調用？

此外，如何確保內存不泄漏在這種情況下？

來源

2011-04-12 Dat Chu

什麼是你期待？析構函數沒有被調用，因爲'std :: runtime_error'沒有被捕獲。 – 2011-04-12 16:57:24

我希望自data_構造完成後，它的析構函數會自動調用。如何確保分配的數據在發生異常時被釋放？ – 2011-04-12 17:01:19

如果從構造函數中拋出一個具體的異常，您的作用域數組可能仍然有一個引用。理想情況下，您希望捕獲此異常並進行處理，而不是解除中止。 – AJG85 2011-04-12 17:01:23

我認爲問題是你的異常未被捕獲，並正在由終止處理程序處理。由於沒有catch來處理異常，因此編譯器無法知道需要「展開」多少。如果您發現異常，則會發生破壞。然後，您可以當然，如果你喜歡再扔它，例如：

#include <QScopedArrayPointer> 
#include <QDebug> 
#include <stdexcept> 

class MyData{ 
public: 
    MyData() { 
    qDebug() << "Construct a data"; 
    } 

    ~MyData() { 
    qDebug() << "Delete a data"; 
    } 

private: 
    float internal_data_; 
}; 

class MyClass{ 
    QScopedArrayPointer<MyData> data_; 
public: 
    MyClass(){ 
    data_.reset(new MyData[10]); 

    throw std::runtime_error("Shit happens"); 
    } 
}; 

int main(int argc, char *argv[]) { 
    try { 
     MyClass a_class; 
    } catch (const std::runtime_error &) { 
     throw; 
    } 
}

輸出如下：

$ ./test2 
Construct a data 
Construct a data 
Construct a data                              
Construct a data                              
Construct a data                              
Construct a data                              
Construct a data 
Construct a data 
Construct a data 
Construct a data 
Delete a data 
Delete a data 
Delete a data 
Delete a data 
Delete a data 
Delete a data 
Delete a data 
Delete a data 
Delete a data 
Delete a data 
terminate called after throwing an instance of 'std::runtime_error' 
    what(): Shit happens 
Aborted

來源

2011-04-12 17:27:58

QScopedArrayPointer守着我的數據，但它仍然是泄漏

回答

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