(SOLVED)fork() and memory sharing?

Question

Let me get this straight, when you fork() a child process this is what happens:
A copy of the parent isn't made just yet-- instead the child has read only rights to the actual parent's memory page. Once the child executes a write call the stack and heap pages are copied and marked with read and write rights.
Questions:
What happens to the shared memory segments? Is this section shared prior and post to the copy/RW escalation? How does the stack, heap and shared memory segments differ?
Last edited by Google (2010-08-25 16:01:17)

Answer 1

Think of shared memory segments as their own entitites, truly separate from the process that created them.  They aren't copied during fork() because they are not technically part of the process's address space. 
A pointer to the shared memory segment may be copied if one exists before you fork, which would allow the child to access the segment created by the parent, but the segment itself is ... well it's shared