Exception caught inside a constructor

Newsgroup: comp.lang.c++

Subject: Exception caught inside a constructor

From: Jarek Blakarz <jumianek@...>

Date: Tue, 9 Jul 2013 07:33:38 -0700 (PDT)



Hi



The following program throws an exception while allocating "A" object.

Allocation fails. An exception is caught inside "C" constructor.

"C" destructor releases memory for both objects. Segmentation fault

occurs while releasing memory for object "A" since the memory has actually not

been allocated for that object.



Please help me to modify the program to work correctly. I want all exceptions

to be caught inside a "C" constructor and no memory leak should happen.



I am aware that this problem may be solved by wrapping ptrA and ptrB in a smart

pointers but I am not interested in this solution.



Thanks for help.



#include <iostream>



using namespace std;



struct A {

A(void)

{

cout << "A" << endl;

}



~A(void)

{

cout << "~A" << endl;

}



void* operator new(size_t size)

{

cout << "A new" << endl;

throw 10; // allocation fails

return ::operator new(size);

}

};



struct B {

B(void)

{

cout << "B" << endl;

}



~B(void)

{

cout << "~B" << endl;

}

};



struct C {

B *ptrB;

A *ptrA;



C(void)

{

cout << "C" << endl;

try {

ptrB = new B;

} catch(...) {

cout << "new B - exception" << endl;

}

try {

ptrA = new A;

} catch(...) {

cout << "new A - exception" << endl;

}

}



~C(void) {

cout << "~C" << endl;

delete ptrB;

delete ptrA;

}

};



int main(void)

{

try {

C c;

} catch(...) {

cout << "main exception handler" << endl;

}

}

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