memory-address

Is the address of an object constant during its life cycle or can it change? I just thought address of an object never changes. Is it JVM dependent? I Haven't found any clear spec. The address of an object in java is not fixed; rather, it may change (subjected to conditions). This is because normally objects are allocated in eden space. Then they move to survivor space, then also to the old generation space if they survived some garbage collection cycles. So it does change. But if the object is allocated in eden space and also garbage collected by staying in the same space, then the address

I know that the code written below is illegal void doSomething(std::string *s){} int main() { doSomething(&std::string("Hello World")); return 0; } The reason is that we are not allowed to take the address of a temporary object. But my question is WHY? Let us consider the following code class empty{}; int main() { empty x = empty(); //most compilers would elide the temporary return 0; } The accepted answer here mentions "usually the compiler consider the temporary and the copy constructed as two objects that are located in the exact same location of memory and avoid the copy." According to the

in c, i tried to print out address of variable and address of some function. I got one is negative value, the other is positive value. My question is: why does C not represent in all negative or all positive value? Here is my code: int foo() { return 0; } int main() { int a; printf("%d\n",&a); printf("%d\n",foo); return 0; } Here is result: -1075908992 134513684 Memory addresses should not be interpreted as signed integers in that way. The sign of the number depends on the highest bit set (assuming two's complement representation, which is used by the vast majority of systems currently in use)

I am reading Operating Systems Concept and I am on the 8th chapter! However I could use some clarification, or reassurance that my understanding is correct. Logical Addresses: Logical addresses are generated by the CPU, according to the book. What exactly does this mean? (In an execute-generated address system..) I assume when code is compiled for a program, the program has no idea where the code will be loaded in memory. All the compiler does is set up a general sketch of the program layout and how the image should be laid out, but doesn't assign any real addresses to it. When the program is

What does <function at 'somewhere'> mean? Example: >>> def main(): ... pass ... >>> main <function main at 0x7f95cf42f320> And maybe there is a way to somehow access it using 0x7f95cf42f320 ? You are looking at the default representation of a function object. It provides you with a name and a unique id, which in CPython happens to be a memory address. You cannot access it using the address; the memory address is only used to help you distinguish between function objects. In other words, if you have two function objects which were originally named main , you can still see that they are

Essentially, how does 4Gb turn into 4GB? If the memory is addressing Bytes, should not the possibilities be 2 (32/8) ? It depends on how you address the data. If you use 32 bits to address each bit , you can address 2 32 bits or 4Gb = 512MB. If you address bytes like most current architectures it will give you 4GB. But if you address much larger blocks you will need less bits to address 4GB. For example if you address each 512-byte block (2^9 bytes) you can address 4GB with 23 bits. FAT16 uses 16 bits to address (maximum) 64KB clusters and therefore can address a maximum 4GB volume. The same

I managed to get the address of a .net object by GCHandle objHandle = GCHandle.Alloc(obj,GCHandleType.WeakTrackResurrection); int address = GCHandle.ToIntPtr(objHandle).ToInt32(); and I can recall the object by Object obj = GCHandle.FromIntPtr(IntPtr(address)).Target; Well, the purpose is to store the address in a native class and have an information of which native object is releated to which .net object. AFAIK the address does not change because of allocing, is it true or does anyone have a better idea to serve my purpose? Thanks VinayC As Tim and thecoop has pointed out, GCHandle.Alloc may