You should always unlock a mutex that you've locked as soon as safely possible (to increase performance). And you should never unlock a mutex that you don't hold a lock for

"dead list" that contains all stopped threads and then have a special cleanup thread that simply waits for an item to be added to the list. The cleanup thread calls pthread_join() to merge it with itself. Now your entire cleanup will be handled neatly and efficiently in a single thread.

mutexes are used to serialize access to *shared data*. Don't use them for non-shared data, and don't use them if your program's logic ensures that only one thread is accessing a particular data structure at a single time.

if you are using shared data, use mutexes for both reading and writing. Surround your read and write sections with pthread_mutex_lock() and pthread_mutex_unlock(), or use them any time a program's invariant is temporarily broken.

pthread_mutex_destroy() does not free the memory used to store the pthread_mutex_t. It's up to you to free() your own memory. Also remember that both pthread_mutex_init() and pthread_mutex_destroy() return zero on success.

pthread_mutex_lock() accepts a single pointer to a mutex to lock. If the mutex already happens to be locked, the caller will go to sleep. When the function returns, the caller will be woken up (obviously), and the caller will also now hold the lock. This call either returns zero on success.

When you call pthread_mutex_trylock() you'll attempt to lock the mutex. If the mutex is currently unlocked you'll get the lock, and this function will return zero. However, if the mutex is locked this call won't block. Rather, it will return a non-zero EBUSY error value.

pthread_cond_wait() simultaneously unlock the mutex (so that other threads can modify the linked list) and wait on the condition (so that pthread_cond_wait() will wake up when it is "signalled" by another thread). Now that the mutex is unlocked, other threads can access and modify the linked list, possibly adding items

pthread_cond_wait() call has not yet returned. Unlocking the mutex happens immediately, but waiting on the condition mycond is normally a blocking operation, meaning that our thread will go to sleep, consuming no CPU cycles until it is woken up.

This is exactly what we want to happen. Our thread is sleeping, waiting for a particular condition to become true, without performing any kind of busy polling that would waste CPU time. From our thread's perspective, it's simply waiting for the pthread_cond_wait() call to return.

Immediately after unlocking the mutex, thread 2 calls the function pthread_cond_broadcast(&mycond). By doing so, thread 2 will cause all threads waiting on the mycond condition variable to immediately wake up. This means that our first thread (which is in the middle of a pthread_cond_wait() call) will now wake up.

After thread 2 called pthread_cond_broadcast(&mymutex) you might think that thread 1's pthread_cond_wait() will immediately return. Not so! Instead, pthread_cond_wait() will perform one last operation: relock mymutex. Once pthread_cond_wait() has the lock, it will then return and allow thread 1 to continue execution.

I know these jokes aren't great, ladies and gentlemen, see this is the problem you run into when you're between impeachments.

In 1817, Czar Alexander I personally founded the Society of Israelite Christians but had less luck defeating Judaism than he'd had defeating Napoleon; gentile serfs and merchants in areas bordering the Pale even showed disturbing new signs of 'Judaizing.'

One thing is for certain: under President Obama, home schooling will become a huge growth industry.

I've been working to make sure that we've got adequate transportation. I've been working to make sure that we can afford energy within our villages and in our communities.

Once I found acting and found that I could get away with it and make a living out of it, I was thrilled.

Art's development should be dialectical and not metaphysical.

I think I grew up with a profound sense of watching people who were good people, who were smart people, who were hardworking people - God, nobody on this Earth worked harder than my mom and dad - and they had very little.

My dad was in the Army and we traveled all over the place and I never failed to win first prize.

I am laughably aggressive, and the rest of the band is very laid back, so we mix well.

I'm not an academic; I'm just a bookish Joe who gets passionate about certain writers and suddenly wants to read everything they've ever written and find out why they wrote it.

A friendship that can cease has never been real.

I'm all about building a relationship with viewers and getting to know them.

Christmas is joy, religious joy, an inner joy of light and peace.

I never actually had a guitar lesson. I taught myself the guitar from piano exercise books, which led me to have a pretty good technique on the guitar and allowed me to find different ways to do things.

I have a private plane. But I fly commercial when I go to environmental conferences.

I've wanted to follow my dad into acting for as long as I can remember. 'I've had a very serious round of dramatic training, and I like action films that take their characters seriously, so I figure I'm making it the best of both worlds if I try to bring some serious acting to a shoot-'em-up picture.

I sometimes don't wash my hair for two weeks. That's pretty disgusting. It's short, so sometimes it's easier to just wet it.

Real biologists who actually do the research will tell you that they almost never find a phenomenon, no matter how odd or irrelevant it looks when they first see it, that doesn't prove to serve a function. The outcome itself may be due to small accidents of evolution.

I am a compassionate human being. I am who I am.

Well, you don't make any demands to Steven Spielberg.

Every man, every woman who has to take up the service of government, must ask themselves two questions: 'Do I love my people in order to serve them better? Am I humble and do I listen to everybody, to diverse opinions in order to choose the best path?' If you don't ask those questions, your governance will not be good.

I love breakfast, and I don't see any reason it has to be cereal and eggs and toast.

But I look at failure as education. In that respect, I am so well-educated.

I am always with you. I do not know where I end and you begin.