Difference between shared memory and pipe in unix?

Question

Hi, what is main difference between shared memory and pipe in unix programming?

Answer 1

Taken from this article

(unnamed) Pipes

• Can switch between blocking and non-blocking mode
• Don't have to free them when done
• Are automatically inherited by children
• Must read and write in a linear fashion

Shared Memory

• Can store structures
• Won't ever block - positive
• Can have as many programs read or write to it as you need
• Won't ever block - negative: must use semaphores or your own spin-locks
• It's possible for it to not be freed even when all programs exit