Improve this question. Ayxan Haqverdili. Ayxan Haqverdili Ayxan Haqverdili EdoardoRosso why do you think it has garbage value? EdoardoRosso no, you're wrong. EdoardoRosso No, it's not garbage. A member pointer isn't a pointer at all. It does not require an object to exist. BillLynch The offsets are 0, , , , respectively. This seems right. The IntelliSense parser correctly identifies the problem, the compiler does not.
A bit tricky to do since this issue can only be detected in the back-end. It is an x64 code generator limitation, objects cannot be larger than 2GB.
Beyond that a very different way to generate the address needs to be used, LEA can't work anymore due to the displacement overflow.
Not available. Show 16 more comments. Active Oldest Votes. Improve this answer. That's about size of an object, and we don't have an object of type Foo here.
AyxanHaqverdili: Strictly speaking, MSVC has a limit on the size of types, which indeed can be slightly different from a limit on the size of objects especially in regard to arrays. Appendix B allows both limits, but suggests only a value for objects. So the answer is that I am causing undefined behavior, or was the compiler supposed to reject this code? It's undefined behavior what happens when you go past the said limit, as in the standard doesn't define what happens when you go past that limit nor does sizeof define what should happen in the example above.
From a usability standpoint, it's sort of ridiculous the compiler doesn't say something about the limitation being reached though. AyxanHaqverdili While there isn't an explicit object of type Foo here, when you do thing like "sizeof", it's often dealing with the object representation of a given type or in respect to an object of a type. For example, a pointer to non-static class member is described as something "which identify members of a given type within objects of a given class".
Add a comment. Ben Voigt Ben Voigt k 38 38 gold badges silver badges bronze badges. Good point. AyxanHaqverdili: Oh my, that still doesn't trigger a "class too large" error? Looks like that particular diagnostic is entirely broken.
To your point that "on gcc compilers any assigned pointer to member evaluates to non-null" : gcc and clang both return null when compiled with -m godbolt. BillLynch that's changing limitations.. I have a bit executable that creates an instance of a class. The constructor and the first function call work fine.
Then some other code not related to this class is executed. After that another function is called and the 'this' pointer is null. The constructor and Foo execute just fine. However when Bar is reached an access violation occurs because 'this' is zero. Does anyone have any hints on how I can debug this further using Visual Studio to try to pin down where it is happening? Hopefully I have solved it, which means it was an edge-case race condition between two threads that was stomping all over the stack.
It could be memory corruption, that is just as likely as you accidentily assigning NULL to the pointer, what you have on the stack in that fuction is the most likely suspect. To help debug this situation, you can run to that function and then step through making sure you have SimDLL as part of the watch list.
Then as soon as it changes value then you can figure out what is going on. Just to be clear - the SimDLL pointer is not null when the problem occurs and the function Bar is called successfully.
So I am guessing that the SimDLL pointer has nothing to do with 'this', even though they should be the same? That is where the corruption seems to happen i. Sample practice syntax for more understanding see below;. As of now, we know that we use Null functions to assign some special value to the pointer variable. By the use of this, we can give them a logical value when they are not pointing to any address in the memory.
Also, we know that pointer holds the memory address, so if we want them to point to some other value, in that case, we can use NULL here. But we have to use this while initiation of the pointer. Now we will see one example and understand its working how it actually works; for more detail, see below;. In this example, we create three different pointers, and all of them point to the NULL here. So as we can see, we have initialized the value for the variable at the time of declaring the variables.
After this, we are making one check here to check and print the value of the pointer. If the statement coming out to be right, then the print statement will be executed; otherwise, it will return. So a null can be an integer value as well when it is not pointing to the memory address.
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