Comparing APIs for Oracle Solaris Threads and POSIX Threads

The Oracle Solaris threads API and the pthreads API are two solutions to the same problem: build parallelism into application software. Although each API is complete, you can safely mix Oracle Solaris threads functions and pthread functions in the same program.

The two APIs do not match exactly, however. Oracle Solaris threads support functions that are not found in pthreads, and pthreads include functions that are not supported in the Oracle Solaris interface. For those functions that do match, the associated arguments might not, although the information content is effectively the same.

By combining the two APIs, you can use features not found in one API to enhance the other API. Similarly, you can run applications that use Oracle Solaris threads exclusively with applications that use pthreads exclusively on the same system.

Major API Differences

Oracle Solaris threads and pthreads are very similar in both API action and syntax. The major differences are listed in Table 6-1 .

Table 6-1 Unique Oracle Solaris Threads and pthreads Features

Oracle Solaris Threads	POSIX Threads
`thr_` prefix for threads function names, `sema_` prefix for semaphore function names	`pthread_` prefix for pthreads function names, `sem_` prefix for semaphore function names
Ability to create “daemon” threads	Cancellation semantics
Suspending and continuing a thread	Scheduling policies

Function Comparison Table

The following table compares Oracle Solaris threads functions with pthreads functions. Note that even when Oracle Solaris threads and pthreads functions appear to be essentially the same, the arguments to the functions can differ.

When a comparable interface is not available either in pthreads or Oracle Solaris threads, a hyphen `-' appears in the column. Entries in the pthreads column that are followed by (3RT) are functions in librt, the POSIX.1b Realtime Extensions library, which is not part of pthreads. Functions in this library provide most of the interfaces specified by the POSIX.1b Realtime Extension.

Table 6-2 Oracle Solaris Threads and POSIX pthreads Comparison

Oracle Solaris Threads	pthreads
`thr_create()`	`pthread_create()`
`thr_exit()`	`pthread_exit()`
`thr_join()`	`pthread_join()`
`thr_yield()`	`sched_yield()`(3RT)
`thr_self()`	`pthread_self()`
`thr_kill()`	`pthread_kill()`
`thr_sigsetmask()`	`pthread_sigmask()`
`thr_setprio()`	`pthread_setschedparam()`
`thr_getprio()`	`pthread_getschedparam()`
`thr_setconcurrency()`	`pthread_setconcurrency()`
`thr_getconcurrency()`	`pthread_getconcurrency()`
`thr_suspend()`	-
`thr_continue()`	-
`thr_keycreate()`	`pthread_key_create()`
-	`pthread_key_delete()`
`thr_setspecific()`	`pthread_setspecific()`
`thr_getspecific()`	`pthread_getspecific()`
-	`pthread_once()`
-	`pthread_equal()`
-	`pthread_cancel()`
-	`pthread_testcancel()`
-	`pthread_cleanup_push()`
-	`pthread_cleanup_pop()`
-	`pthread_setcanceltype()`
-	`pthread_setcancelstate()`
`mutex_lock()`	`pthread_mutex_lock()`
`mutex_unlock()`	`pthread_mutex_unlock()`
`mutex_trylock()`	`pthread_mutex_trylock()`
`mutex_init()`	`pthread_mutex_init()`
`mutex_destroy()`	`pthread_mutex_destroy()`
`cond_wait()`	`pthread_cond_wait()`
`cond_timedwait()`	`pthread_cond_timedwait()`
`cond_reltimedwait()`	`pthread_cond_reltimedwait_np()`
`cond_signal()`	`pthread_cond_signal()`
`cond_broadcast()`	`pthread_cond_broadcast()`
`cond_init()`	`pthread_cond_init()`
`cond_destroy()`	`pthread_cond_destroy()`
`rwlock_init()`	`pthread_rwlock_init()`
`rwlock_destroy()`	`pthread_rwlock_destroy()`
`rw_rdlock()`	`pthread_rwlock_rdlock()`
`rw_wrlock()`	`pthread_rwlock_wrlock()`
`rw_unlock()`	`pthread_rwlock_unlock()`
`rw_tryrdlock()`	`pthread_rwlock_tryrdlock()`
`rw_trywrlock()`	`pthread_rwlock_trywrlock()`
-	`pthread_rwlockattr_init()`
-	`pthread_rwlockattr_destroy()`
-	`pthread_rwlockattr_getpshared()`
-	`pthread_rwlockattr_setpshared()`
`sema_init()`	`sem_init()`(3RT)
`sema_destroy()`	`sem_destroy()`(3RT)
`sema_wait()`	`sem_wait()`(3RT)
`sema_post()`	`sem_post()`(3RT)
`sema_trywait()`	`sem_trywait()`(3RT)
`fork1()`	`fork()`
-	`pthread_atfork()`
`forkall()`, multiple thread copy	-
-	`pthread_mutexattr_init()`
-	`pthread_mutexattr_destroy()`
`type` argument in `mutex_init()`	`pthread_mutexattr_setpshared()`
-	`pthread_mutexattr_getpshared()`
-	`pthread_mutex_attr_settype()`
-	`pthread_mutex_attr_gettype()`
-	`pthread_condattr_init()`
-	`pthread_condattr_destroy()`
`type` argument in `cond_init()`	`pthread_condattr_setpshared()`
-	`pthread_condattr_getpshared()`
-	`pthread_attr_init()`
-	`pthread_attr_destroy()`
`THR_BOUND` flag in `thr_create()`	`pthread_attr_setscope()`
-	`pthread_attr_getscope()`
-	`pthread_attr_setguardsize()`
-	`pthread_attr_getguardsize()`
`stack_size` argument in `thr_create()`	`pthread_attr_setstacksize()`
-	`pthread_attr_getstacksize()`
`stack_addr` argument in `thr_create()`	`pthread_attr_setstack()`
-	`pthread_attr_getstack()`
`THR_DETACH` flag in `thr_create()`	`pthread_attr_setdetachstate()`
-	`pthread_attr_getdetachstate()`
-	`pthread_attr_setschedparam()`
-	`pthread_attr_getschedparam()`
-	`pthread_attr_setinheritsched()`
-	`pthread_attr_getinheritsched()`
-	`pthread_attr_setsschedpolicy()`
-	`pthread_attr_getschedpolicy()`

To use the Oracle Solaris threads functions described in this chapter for Solaris 9 and previous releases, you must link with the Oracle Solaris threads library -lthread .

Operation is virtually the same for both Oracle Solaris threads and for pthreads, even though the function names or arguments might differ. Only a brief example consisting of the correct include file and the function prototype is presented. Where return values are not given for the Oracle Solaris threads functions, see the appropriate pages in man pages section 3: Basic Library Functions for the function return values.

For more information on Oracle Solaris related functions, see the related pthreads documentation for the similarly named function.

Where Oracle Solaris threads functions offer capabilities that are not available in pthreads, a full description of the functions is provided.

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