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Senthilvel Samatharman Guest
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Posted: Thu Mar 04, 2004 7:12 am Post subject: Overloading operator delete |
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I am just curious about the case 3 in the follwouing program.
I understand that case 1 is the right way to overload,
while Case 2 is erroneous.
But i do think that the implementation of operator delete of Case 3 should
end up in recursion but works fine.
Am i wrong or is it the problem with the VC6 compiler?
thanks ,
Senthil.
#include <iostream>
using namespace std;
class Test
{
private:
int s;
public:
Test(){
cout<<"Test::Test()"<
}
// Case 1 : This works fine
void * operator new(size_t size)
{
return ::operator new (size); // Use global operator new
}
// This also works fine
void operator delete(void* p)
{
::operator delete(p); // Global operator delete
}
/**************************************************************/
// Case 2 : This causes infinite recursion
void * operator new(size_t size)
{
return operator new (size); // Use local operator new
}
// This causes infinite recursion
void operator delete(void* p)
{
operator delete(p); // Use local operator delete
}
/**************************************************************/
// Case 3 : This causes a compile error
void * operator new(size_t size)
{
return new(size); // Use local new operator inside "operator new"
}
// Case 3: This does not cause a compile error or does not cause a
recursion.
void operator delete(void* p)
{
delete p;
}
};
int main()
{
Test* pTest = new Test;
delete pTest;
return 0;
}
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Nick Hounsome Guest
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Posted: Fri Mar 05, 2004 7:01 pm Post subject: Re: Overloading operator delete |
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"Senthilvel Samatharman" <me (AT) somewhere (DOT) com> wrote
| Quote: | I am just curious about the case 3 in the follwouing program.
I understand that case 1 is the right way to overload,
while Case 2 is erroneous.
But i do think that the implementation of operator delete of Case 3 should
end up in recursion but works fine.
Am i wrong or is it the problem with the VC6 compiler?
thanks ,
Senthil.
#include
using namespace std;
class Test
{
private:
int s;
public:
Test(){
cout<<"Test::Test()"<
}
[snip]
// Case 3: This does not cause a compile error or does not cause a
recursion.
void operator delete(void* p)
{
delete p;
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This is ok because you are deleting a void* NOT a Test*
Consider:
void operator delete(void* p)
{
void* x = new int;
delete x; // you wouldn't expect this to recurse would you
x = p;
delete x; // what's the difference? None!
delete (Test*)p; // Now THIS is recursive
}
| Quote: | }
};
int main()
{
Test* pTest = new Test;
delete pTest;
return 0;
}
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