Re: CS352 Homework 10 / General Question

[David L. Rager]

MAP_PRIVATE means that any changes to the memory-mapped region can
only be seen by that particular process. MAP_SHARED means that the
changes can be seen by other processes. Guess which one you need if
you want to change a file in a way that persists beyond one particular
process.

On Mon, Nov 23, 2009 at 9:42 PM, wrote:
> I think this could help me in my solution to 10.14 since 10.5 is very
> similar in scope. In the solution given to 10.5, bufp gets the flag
> "MAP_PRIVATE". Would using "MAP_SHARED" have a negative effect on the
> program? I guess what I'm trying to say is that I don't understand the
> difference between the two and the book doesn't really help. Could you
> explain the difference and/or effect of using one over the other? Thank you
> in advance for any help.

[Matt Miller]

Has anyone figure out what this line is for? i.e., what purpose does it serve in the code for actually solving this problem, if any?

void *mmap(void *start, size_t length, int prot , int flags, int fd, off_t offset);

It looks like a function prototype, but it returns void, which only adds to my confusion.

This problem is frustrating because at this point I know exactly what needs to be done conceptually, but the code fragments and hints given with it don't make a lot of sense to me and I've spent more time trying to figure out what the hints are trying to say than what the question is asking.