Under what set of conditions is it safe to use std::memcpy to copy from one object to another? For example, what conditions must T, src and dest satisfy for the following to be safe: template &lt...

More specifically, assuming A is an accessible base class of B, does the following code produce undefined behavior, and is the assertion guarenteed not to fire according to the standard? void test...

This is a big question, so I'm asking for a reference rather than a booklet-sized answer. I'm going through Stroustrup's Tour of C++, and it seems like the way objects are laid out is memory is fun...

Intro: I used the JOL (Java Object Layout) tool to analyze the internal and external fragmentation of Java objects for research purpose. While doing so, I stumbled across the following: x@pc:~/U...

I found this in a website while reading about virtual inheritance in c++ When multiple inheritance is used, it is sometimes necessary to use virtual inheritance. A good example for this is the sta...

I know that constant variables outside classes can be optimized directly into function calls by the compiler, but is it legal for the compiler to do the same for constant class variables? If there...

In my first example I have two bitfields using int64_t. When I compile and get the size of the class I get 8. class Test { int64_t first : 40; int64_t second : 24; }; int main() { std::cout &l...

I've been asked in a recent interview about C++ struct fields alignment and theoretized that C and C++ follows the same strategy in struct packing. Hovewer, it was the wrong assumption. The inter...

Could you give me some information on what is exactly stored in object header? I know, that it's probably JVM dependent, but maybe for HotSpot at least? I'm looking for exact description specifical...

Can I treat consecutive data members of the same type as a range? For example: struct X { int a, b, c, d, e; }; X x = {42, 13, 97, 11, 31}; std::sort(&x.a, &x.a + 5); // kosher?

Where in memory is the vtable stored?