You're working on a platform where pointers are aligned to 8 bytes. Since the virtual table pointer is typically the first thing in the layout of an object, it too must be aligned to 8 bytes. So padding 4 bytes are inserted after the int
member, that's why you get a size of 16 (8 bytes for the vf table pointer, 4 for the int and 4 padding bytes).
Size of class with virtual function
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18-10-2022 - |
Question
I was revising the C++ concepts, but I am stuck with a very simple code
#include <iostream>
using namespace std;
class foo {
public:
//int i;
void virtual foobar()
{
cout << "foobar\n";
}
};
int main()
{
foo f;
cout << sizeof(f) << endl;
//cout << sizeof(f.i) << endl;
return 1;
}
The output of the above code is 8 But when I removed comments from the code Output is 16 and 4
I did not understand when the class have no member variable present then VPTR size is 8 but after adding a variable size becomes 12.
Solution
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