Threads

Now it is time to look at multithreaded processes. The programming interface for threads is the POSIX threads API, which was first defined in the IEEE POSIX 1003.1c standard (1995) and is commonly known as pthreads. It is implemented as an additional part of the C-library, libpthread.so. There have been two implementations of pthreads over the last 15 years or so: LinuxThreads and Native POSIX Thread Library (NPTL). The latter is much more compliant with the specification, particularly with regard to the handling of signals and process IDs. It is pretty dominant now, but you may come across some older versions of uClibc that use LinuxThreads.

Creating a new thread

The function to create a thread is pthread_create(3):

int pthread_create(pthread_t *thread, const pthread_attr_t *attr, 
   void *(*start_routine) (void *), void *arg);

It creates a new thread of execution that begins in the function start_routine and places a descriptor in the pthread_t pointed to by thread. It inherits the...