please tell me the difference between a condition variable and a semaphore?

<<snip>> Look up the meanings of the terms and then figure out what's different about them.

oh come on man. What the flower is wrong with you guys. You are supposed to post something valuable. Not smurfing links to my own posts.

commented: "You are supposed to post something valuable." - WRONG, you're supposed to show something which makes you more deserving that the average shrub posting homework without effort. -4

>You are supposed to post something valuable

And you are not? Posting one liner questions one after another gives the impression that you are not at all putting in effort for solving your own queries. How about something like:

I've read about X v/s Y at and am still having doubts about why Z happens; any pointers appreciated

Don't get me wrong; the first reply to your post does go out of the line but it's kinda difficult to not get irritated given a lack of effort on your part.