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Apr 10th, 2009

destruction of a global variable?

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Hello, I have a question, when does a global variable get destructed?

ex.

c++ Syntax (Toggle Plain Text)
#include <iostream>
using namespace std;
class simple {
    public:
    int *i;
    simple(int ni){
        i = new int(ni);
    }
    ~simple(){
        delete i;
    }
}
simple simple1(10);
//for simplicity no command line
int main(){
     cout<<*(simple.i)
}
#include <iostream>
using namespace std;
class simple {
    public:
    int *i;
    simple(int ni){
        i = new int(ni);
    }
    ~simple(){
        delete i;
    }
}
simple simple1(10);
//for simplicity no command line
int main(){
     cout<<*(simple.i)
}

when will simple::~simple() be called? after the execution of main finishes?

sciwizeh

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Apr 11th, 2009

Re: destruction of a global variable?

Quote ...

Hello, I have a question, when does a global variable get destructed?

well i guess when the program terminates , the global variable is freed by the OS .

rahul8590

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Apr 11th, 2009

Re: destruction of a global variable?

simple::~simple is a destructor and is called automatically when the object is being destructed, you can never call it yourself ...

tux4life

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Apr 11th, 2009

Re: destruction of a global variable?

Click to Expand / Collapse Quote originally posted by sciwizeh ...

Hello, I have a question, when does a global variable get destructed?

The compiler arranges for code to get executed both before main() is called and after it returns. Before main(), global constructors are called. After main(), global destructors are called in opposite order of their construction.

boblied

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Apr 11th, 2009

Re: destruction of a global variable?

Click to Expand / Collapse Quote originally posted by sciwizeh ...

when will simple::~simple() be called? after the execution of main finishes?

When the execution of main finishes, just before the program exits the destructor will be called ...

tux4life

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Apr 11th, 2009

Re: destruction of a global variable?

You can easily test that, just put some messages in the destructor and some in the program itself to see its place right?

Clockowl

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Apr 11th, 2009

Re: destruction of a global variable?

Click to Expand / Collapse Quote originally posted by Clockowl ...

You can easily test that, just put some messages in the destructor and some in the program itself to see its place right?

Yes, that's true. The C++ Standard requires that objects associated with std::cin, std::cout and std::cerr are destroyes after destruction of user-defined objects with static duration:

Quote ...

Constructors and destructors for static objects can access these objects to read input from stdin or write output to
stdout or stderr.

ArkM

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Apr 11th, 2009

Re: destruction of a global variable?

Click to Expand / Collapse Quote originally posted by ArkM ...

Yes, that's true. The C++ Standard requires that objects associated with std::cin, std::cout and std::cerr are destroyes after destruction of user-defined objects with static duration:

standard input , output and the error is a operating system concept, as in linux and they are never destructed , but C++ object associated with them get destructed after destruction of user-defined objects with static duration.

Last edited by NicAx64; Apr 11th, 2009 at 3:17 pm.

NicAx64

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Apr 11th, 2009

Re: destruction of a global variable?

Click to Expand / Collapse Quote originally posted by NicAx64 ...

standard input , output and the error is a operating system concept, as in linux and they are never destructed , but C++ object associated with them get destructed after destruction of user-defined objects with static duration.

It seems you did not understand my post. What for you reprint the same sentence?

Last edited by ArkM; Apr 11th, 2009 at 4:51 pm.

ArkM

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