POSIX Threads

1
POSIX Threads
2
Compiling

• Include pthread.h
• Solaris
• cc mt -lpthread
• Linux
• gcc pthread
• Do not manually define _REENTRANT, or link
  against any libraries.

3
Creation

• int pthread_create(pthread_t thread, const
  pthread_attr_t attr, void (start_routine)(void
  ), void arg)
• Example
• extern "C" void run(void )
• int ec pthread_create(tid, NULL, run, NULL)
• Passing data
• int data
• ec pthread_create(tid, NULL, run, data)

4
Attributes

• int pthread_attr_init(pthread_attr_t attr)
• int pthread_attr_setdetachstate(pthread_attr_t
  attr, int detachstate)
• PTHREAD_CREATE_DETACHED
• PTHREAD_CREATE_JOINABLE
• int pthread_attr_setscope(pthread_attr_t attr,
  int scope)
• PTHREAD_SCOPE_SYSTEM
• PTHREAD_SCOPE_PROCESS

5
Mutexes

• int pthread_mutex_init(pthread_mutex_t mutex,
  const pthread_mutexattr_t mutexattr)
• ?
• pthread_mutex_t lock
• void f()
• pthread_mutex_lock(lock)
• pthread_mutex_unlock(lock)
• void g()
• pthread_mutex_lock(lock)
• f()
• pthread_mutex_unlock(lock)
• Attributes
• pthread_mutexattr_init
• __linux
• __sun

6
Condition Variables

• int pthread_cond_init(pthread_cond_t cond,
  pthread_condattr_t cond_attr)
• pthread_cond_signal
• Awakens one waiter.
• pthread_cond_broadcast
• Awakens all waiters.
• pthread_cond_wait
• Atomically releases mutex and blocks. Avoids
  missed signals.