Code sample two threads updating
A condition variable must always be associated with a mutex to avoid a race condition created by one thread preparing to wait and another thread which may signal the condition before the first thread actually waits on it resulting in a deadlock.The thread will be perpetually waiting for a signal that is never sent.Poor software logic can also lead to a deadlock condition. Note: Race conditions abound with this example because count is used as the condition and can't be locked in the while statement without causing deadlock. The POSIX thread libraries are a standards based thread API for C/C .It allows one to spawn a new concurrent process flow.
One waits for the completion of the threads with a join.While most effective on a multiprocessor system, gains are also found on uniprocessor systems which exploit latency in I/O and other system functions which may halt process execution.(One thread may execute while another is waiting for I/O or some other system latency.) Parallel programming technologies such as MPI and PVM are used in a distributed computing environment while threads are limited to a single computer system.Overview This is a brief tutorial on how write parallel applications using POSIX threads.Basically, this document is a short version of DEC's 300 page manual; it is intended to provide sufficient information to enable the development of reasonably sophisticated parallel scientific codes in C. A thread is a sequence of instructions to be executed within a program.