What kind of code can be called “re-entrant”?

Question

Could someone tell me what code can be called \"re-entrant\" code?

I came across this word when reading some real time operating system. What disciplines must be st

Answer 1

Code that can be called by different threads running in parallel. So, the code:

1. can have local variables (allocated on each thread's stack)
2. should have guarded global and static variables, since the threads will be sharing them and there will be a race condition here.