What is Re-Entrant

**katrina** · 9th January 2006, 00:19

My grandmother had a bedroom in her house that was non-re-entrant. If you shut the door on your way out, it would automatically lock and you couldn't get back in without taking the door off the hinges or climbing through the window... I do wonder why she never just bought another door knob... (My dad had to take her door off a couple of times lol) oh well!

Katrina

**wysota** · 9th January 2006, 01:21

That's more likely a deadlock

Reentrancy is about having more than one entity operating on the same object (so reentrant room is when more than one person can fit there without spreading havoc).

**Thomas** · 9th January 2006, 23:06

Originally Posted by wysota

That's more likely a deadlock

Reentrancy is about having more than one entity operating on the same object (so reentrant room is when more than one person can fit there without spreading havoc).

Hmm, I would say, reentrancy is a room with more than one door.

**Dusdan** · 9th January 2006, 23:19

Originally Posted by Thomas

Hmm, I would say, reentrancy is a room with more than one door.

nice definition, I think it fits quite well

**wysota** · 10th January 2006, 00:34

Originally Posted by Thomas

Hmm, I would say, reentrancy is a room with more than one door.

Hmmm... I wouldn't agree... That would be two entry points, not reentrancy. Better would be to say that reentrancy is a bedroom with more than one bed. Why? Because it is not about entering the function, but about behaviour inside it. For me a room with more than one door is an example of a locking mechanism, like a semaphore.

**Thomas** · 11th January 2006, 00:39

Exactly, wysota.

It depends on the point of view what the bedrooom and the bed are. If the bed is a kind of member in the method bedroom, the doors represent bedroom using threads. In this way, every bed would represent another member inside the bedroom.

**wysota** · 11th January 2006, 00:49

The point is reentrancy is not about threads. An object may not be reentrant even in a single threaded environment.

But let's leave that, we've come waaaaay offtopic

(I like that smiley...)

**Thomas** · 11th January 2006, 03:00

I know. It was meant as an example for other objects trying to call bedroom.

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