I'm new to operating systems and ran a simple C code snippet on an online compiler. It uses the `fork()` function to create a child process, and I'm trying to understand why the addresses of the variables 'a' and 'b' in the child process differ from those in the parent process. After the `fork()`, I expected them to share the same stack and have identical addresses for these variables, but that's not the case. Can anyone elaborate on why this happens?
2 Answers
Exactly! The `fork()` creates a copy of the process, and consequently, it also allocates new memory for the child. Hence, each process may have the same logical structure, but the memory addresses are different. It's important to remember that every variable has its own stack frame in each process! Keep digging into these concepts!
When you call `fork()`, it creates a child process with a separate memory space from the parent process, including their stacks. Even though both processes use the same code, they have individual copies of the variables, which is why their addresses appear different. It's a common misconception to think they would share the same memory locations after the fork, but that’s not how it works!
Got it! So, if they have separate stacks, that makes total sense. Just one more question, what happens if the child modifies a variable after forking?