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The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License.
You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License.
When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
cc -mt [ flag... ] file... [ -lrt library... ]
#include <pthread.h>
cc -mt [ flag... ] file... [ library... ]
#include <sched.h>
#include <thread.h>
POSIX and Solaris threads each have their own implementation within libc(3LIB). Both implementations are interoperable, their functionality similar, and can be used within the same application. Only POSIX threads are guaranteed to be fully portable to other POSIX-compliant environments. POSIX and Solaris threads require different source, include files and linking libraries. See SYNOPSIS.
Most of the POSIX and Solaris threading functions have counterparts with each other. POSIX function names, with the exception of the semaphore names, have a "pthread" prefix. Function names for similar POSIX and Solaris functions have similar endings. Typically, similar POSIX and Solaris functions have the same number and use of arguments.
POSIX pthreads and Solaris threads differ in the following ways:
POSIX threads are more portable.
POSIX threads establish characteristics for each thread according to configurable attribute objects.
POSIX pthreads implement thread cancellation.
POSIX pthreads enforce scheduling algorithms.
POSIX pthreads allow for clean-up handlers for fork(2) calls.
Solaris threads can be suspended and continued.
Solaris threads implement daemon threads, for whose demise the process does not wait.
The following table compares the POSIX pthreads and Solaris threads functions. When a comparable interface is not available either in POSIX pthreads or Solaris threads, a hyphen (-) appears in the column.
| POSIX | Solaris |
| pthread_create() | thr_create() |
| pthread_attr_init() | - |
| pthread_attr_setdetachstate() | - |
| pthread_attr_getdetachstate() | - |
| pthread_attr_setinheritsched() | - |
| pthread_attr_getinheritsched() | - |
| pthread_attr_setschedparam() | - |
| pthread_attr_getschedparam() | - |
| pthread_attr_setschedpolicy() | - |
| pthread_attr_getschedpolicy() | - |
| pthread_attr_setscope() | - |
| pthread_attr_getscope() | - |
| pthread_attr_setstackaddr() | - |
| pthread_attr_getstackaddr() | - |
| pthread_attr_setstacksize() | - |
| pthread_attr_getstacksize() | - |
| pthread_attr_getguardsize() | - |
| pthread_attr_setguardsize() | - |
| pthread_attr_destroy() | - |
| - | thr_min_stack() |
| POSIX | Solaris |
| pthread_exit() | thr_exit() |
| pthread_join() | thr_join() |
| pthread_detach() | - |
| POSIX | Solaris |
| pthread_key_create() | thr_keycreate() |
| pthread_setspecific() | thr_setspecific() |
| pthread_getspecific() | thr_getspecific() |
| pthread_key_delete() | - |
| POSIX | Solaris |
| pthread_sigmask() | thr_sigsetmask() |
| pthread_kill() | thr_kill() |
| POSIX | Solaris |
| pthread_self() | thr_self() |
| pthread_equal() | - |
| - | thr_main() |
| POSIX | Solaris |
| - | thr_yield() |
| - | thr_suspend() |
| - | thr_continue() |
| pthread_setconcurrency() | thr_setconcurrency() |
| pthread_getconcurrency() | thr_getconcurrency() |
| pthread_setschedparam() | thr_setprio() |
| pthread_setschedprio() | thr_setprio() |
| pthread_getschedparam() | thr_getprio() |
| POSIX | Solaris |
| pthread_cancel() | - |
| pthread_setcancelstate() | - |
| pthread_setcanceltype() | - |
| pthread_testcancel() | - |
| pthread_cleanup_pop() | - |
| pthread_cleanup_push() | - |
| POSIX | Solaris |
| pthread_mutex_init() | mutex_init() |
| pthread_mutexattr_init() | - |
| pthread_mutexattr_setpshared() | - |
| pthread_mutexattr_getpshared() | - |
| pthread_mutexattr_setprotocol() | - |
| pthread_mutexattr_getprotocol() | - |
| pthread_mutexattr_setprioceiling() | - |
| pthread_mutexattr_getprioceiling() | - |
| pthread_mutexattr_settype() | - |
| pthread_mutexattr_gettype() | - |
| pthread_mutexattr_setrobust() | - |
| pthread_mutexattr_getrobust() | - |
| pthread_mutexattr_destroy() | - |
| pthread_mutex_setprioceiling() | - |
| pthread_mutex_getprioceiling() | - |
| pthread_mutex_lock() | mutex_lock() |
| pthread_mutex_trylock() | mutex_trylock() |
| pthread_mutex_unlock() | mutex_unlock() |
| pthread_mutex_destroy() | mutex_destroy() |
| POSIX | Solaris |
| pthread_cond_init() | cond_init() |
| pthread_condattr_init() | - |
| pthread_condattr_setpshared() | - |
| pthread_condattr_getpshared() | - |
| pthread_condattr_destroy() | - |
| pthread_cond_wait() | cond_wait() |
| pthread_cond_timedwait() | cond_timedwait() |
| pthread_cond_signal() | cond_signal() |
| pthread_cond_broadcast() | cond_broadcast() |
| pthread_cond_destroy() | cond_destroy() |
| POSIX | Solaris |
| pthread_rwlock_init() | rwlock_init() |
| pthread_rwlock_rdlock() | rw_rdlock() |
| pthread_rwlock_tryrdlock() | rw_tryrdlock() |
| pthread_rwlock_wrlock() | rw_wrlock() |
| pthread_rwlock_trywrlock() | rw_trywrlock() |
| pthread_rwlock_unlock() | rw_unlock() |
| pthread_rwlock_destroy() | rwlock_destroy() |
| pthread_rwlockattr_init() | - |
| pthread_rwlockattr_destroy() | - |
| pthread_rwlockattr_getpshared() | - |
| pthread_rwlockattr_setpshared() | - |
| POSIX | Solaris |
| sem_init() | sema_init() |
| sem_open() | - |
| sem_close() | - |
| sem_wait() | sema_wait() |
| sem_trywait() | sema_trywait() |
| sem_post() | sema_post() |
| sem_getvalue() | - |
| sem_unlink() | - |
| sem_destroy() | sema_destroy() |
| POSIX | Solaris |
| pthread_atfork() | - |
| POSIX | Solaris |
| pthread_once() | - |
| POSIX | Solaris |
| - | thr_stksegment() |
Multithreaded behavior is asynchronous, and therefore, optimized for concurrent and parallel processing. As threads, always from within the same process and sometimes from multiple processes, share global data with each other, they are not guaranteed exclusive access to the shared data at any point in time. Securing mutually exclusive access to shared data requires synchronization among the threads. Both POSIX and Solaris implement four synchronization mechanisms: mutexes, condition variables, reader/writer locking (optimized frequent-read occasional-write mutex), and semaphores.
Synchronizing multiple threads diminishes their concurrency. The coarser the grain of synchronization, that is, the larger the block of code that is locked, the lesser the concurrency.
If a threads program calls fork(2), it implicitly calls fork1(2), which replicates only the calling thread. Should there be any outstanding mutexes throughout the process, the application should call pthread_atfork(3C) to wait for and acquire those mutexes prior to calling fork().
Solaris supports the following three POSIX scheduling policies:
SCHED_OTHER
Traditional Timesharing scheduling policy. It is based on the timesharing (TS) scheduling class.
SCHED_FIFO
First-In-First-Out scheduling policy. Threads scheduled to this policy, if not preempted by a higher priority, will proceed until completion. Such threads are in real-time (RT) scheduling class. The calling process must have a effective user ID of 0.
SCHED_RR
Round-Robin scheduling policy. Threads scheduled to this policy, if not preempted by a higher priority, will execute for a time period determined by the system. Such threads are in real-time (RT) scheduling class and the calling process must have a effective user ID of 0.
In addition to the POSIX-specified scheduling policies above, Solaris also supports these scheduling policies:
SCHED_IA
Threads are scheduled according to the Inter-Active Class (IA) policy as described in priocntl(2).
SCHED_FSS
Threads are scheduled according to the Fair-Share Class (FSS) policy as described in priocntl(2).
SCHED_FX
Threads are scheduled according to the Fixed-Priority Class (FX) policy as described in priocntl(2).
Only scheduling policy supported is SCHED_OTHER, which is timesharing, based on the TS scheduling class.
In a multithreaded application, EINTR can be returned from blocking system calls when another thread calls forkall(2).
The -mt compiler option compiles and links for multithreaded code. It compiles source files with -D_REENTRANT and augments the set of support libraries properly.
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| MT-Level | MT-Safe, Fork 1-Safe |
crle(1), fork(2), priocntl(2), libpthread(3LIB), librt(3LIB), libthread(3LIB), pthread_atfork(3C), pthread_create(3C), attributes(5), standards(5)
Linker and Libraries Guide