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Multithreaded Programming Guide Oracle Solaris 11.1 Information Library |
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Multithreaded Programming Guide Oracle Solaris 11.1 Information Library |
1. Covering Multithreading Basics
4. Programming with Synchronization Objects
Mutual Exclusion Lock Attributes
Initializing a Mutex Attribute Object
pthread_mutexattr_init Return Values
Destroying a Mutex Attribute Object
pthread_mutexattr_destroy Syntax
pthread_mutexattr_destroy Return Values
pthread_mutexattr_setpshared Syntax
pthread_mutexattr_setpshared Return Values
pthread_mutexattr_getpshared Syntax
pthread_mutexattr_getpshared Return Values
Setting the Mutex Type Attribute
pthread_mutexattr_settype Syntax
pthread_mutexattr_settype Return Values
Getting the Mutex Type Attribute
pthread_mutexattr_gettype Syntax
pthread_mutexattr_gettype Return Values
Setting the Mutex Attribute's Protocol
pthread_mutexattr_setprotocol Syntax
pthread_mutexattr_setprotocol Return Values
Getting the Mutex Attribute's Protocol
pthread_mutexattr_getprotocol Syntax
pthread_mutexattr_getprotocol Return Values
Setting the Mutex Attribute's Priority Ceiling
pthread_mutexattr_setprioceiling Syntax
pthread_mutexattr_setprioceiling Return Values
Getting the Mutex Attribute's Priority Ceiling
pthread_mutexattr_getprioceiling Syntax
pthread_mutexattr_getprioceiling Return Values
Setting the Mutex's Priority Ceiling
pthread_mutex_setprioceiling Syntax
pthread_mutex_setprioceiling Return Values
Getting the Mutex's Priority Ceiling
pthread_mutex_getprioceiling Syntax
pthread_mutex_getprioceiling Return Values
Setting the Mutex's Robust Attribute
pthread_mutexattr_setrobust_np Syntax
pthread_mutexattr_setrobust_np Return Values
Getting the Mutex's Robust Attribute
pthread_mutexattr_getrobust_np Syntax
pthread_mutexattr_getrobust_np Return Values
pthread_mutex_init Return Values
pthread_mutex_consistent_np Syntax
pthread_mutex_consistent_np Return Values
pthread_mutex_lock Return Values
pthread_mutex_unlock Return Values
Locking a Mutex Without Blocking
pthread_mutex_trylock Return Values
Locking a Mutex Before a Specified Absolute Time
pthread_mutex_timedlock() Syntax
pthread_mutex_timedlock() Return Values
Locking a Mutex Within a Specified Time Interval
pthread_mutex_reltimedlock_np() Syntax
pthread_mutex_reltimedlock_np() Return Values
pthread_mutex_destroy Return Values
Code Examples of Mutex Locking
Examples of Using Lock Hierarchies
Examples of Using Nested Locking With a Singly-Linked List
Example of Nested Locking With a Circularly-Linked List
pthread_spin_init() Return Values
pthread_spin_lock() Return Values
Acquiring a Non-Blocking Spin Lock
pthread_spin_trylock() Return Values
pthread_spin_unlock() Return Values
pthread_spin_destroy() Return Values
Initializing a Condition Variable Attribute
pthread_condattr_init Return Values
Removing a Condition Variable Attribute
pthread_condattr_destroy Syntax
pthread_condattr_destroy Return Values
Setting the Scope of a Condition Variable
pthread_condattr_setpshared Syntax
pthread_condattr_setpshared Return Values
Getting the Scope of a Condition Variable
pthread_condattr_getpshared Syntax
pthread_condattr_getpshared Return Values
Setting the Clock Selection Condition Variable
pthread_condattr_setclock Syntax
pthread_condattr_setclock Returns
Getting the Clock Selection Condition Variable
pthread_condattr_getclock Syntax
pthread_condattr_getclock Returns
Initializing a Condition Variable
pthread_cond_init Return Values
Blocking on a Condition Variable
pthread_cond_wait Return Values
pthread_cond_signal Return Values
Blocking Until a Specified Time
pthread_cond_timedwait Return Values
Blocking For a Specified Interval
pthread_cond_reltimedwait_np Syntax
pthread_cond_reltimedwait_np Return Values
pthread_cond_broadcast Return Values
Destroying the Condition Variable State
pthread_cond_destroy Return Values
Synchronization With Semaphores
Initializing Semaphores With Intraprocess Scope
Initializing Semaphores With Interprocess Scope
Decrementing a Semaphore Count
Destroying the Semaphore State
Producer and Consumer Problem Using Semaphores
Initializing a Read-Write Lock Attribute
pthread_rwlockattr_init Syntax
pthread_rwlockattr_init Return Values
Destroying a Read-Write Lock Attribute
pthread_rwlockattr_destroy Syntax
pthread_rwlockattr_destroy Return Values
Setting a Read-Write Lock Attribute
pthread_rwlockattr_setpshared Syntax
pthread_rwlockattr_setpshared Return Values
Getting a Read-Write Lock Attribute
pthread_rwlockattr_getpshared Syntax
pthread_rwlockattr_getpshared Return Values
Initializing a Read-Write Lock
pthread_rwlock_init Return Values
Acquiring the Read Lock on Read-Write Lock
pthread_rwlock_rdlock Return Values
Acquiring a Read Lock on a Read-Write Lock Before a Specified Absolute Time
pthread_rwlock_timedrdlock Syntax
pthread_rwlock_timedrdlock Return Values
Acquiring a Non-Blocking Read Lock on a Read-Write Lock
pthread_rwlock_tryrdlock Syntax
pthread_rwlock_tryrdlock Return Values
Acquiring the Write Lock on a Read-Write Lock
pthread_rwlock_wrlock Return Values
Acquiring a Non-blocking Write Lock on a Read-Write Lock
pthread_rwlock_trywrlock Syntax
pthread_rwlock_trywrlock Return Values
Acquiring a Write Lock on a Read-Write Lock Before a Specified Absolute Time
pthread_rwlock_timedwrlock Syntax
pthread_rwlock_timedwrlock Returns
pthread_rwlock_unlock Return Values
pthread_rwlock_destroy Return Values
Initializing a Synchronization Barrier
pthread_barrier_init() Return Values
Waiting for Threads to Synchronize at a Barrier
pthread_barrier_wait() Return Values
Destroying a Synchronization Barrier
pthread_barrier_destroy Syntax
pthread_barrier_destroy Return Values
Initializing a Barrier Attributes Object
pthread_barrierattr_init() Syntax
pthread_barrierattr_init() Return Values
Setting a Barrier Process-Shared Attribute
pthread_barrierattr_setpshared() Syntax
pthread_barrierattr_setpshared() Return Values
Getting a Barrier Process-Shared Attribute
pthread_barrierattr_getpshared() Syntax
pthread_barrierattr_getpshared() Return Values
Destroying a Barrier Attributes Object
Synchronization Across Process Boundaries
Producer and Consumer Problem Example
5. Programming With the Oracle Solaris Software
6. Programming With Oracle Solaris Threads
In cases where you must wait for a number of tasks to be completed before an overall task can proceed, barrier synchronization can be used. POSIX threads specifies a synchronization object called a barrier, along with barrier functions. The functions create the barrier, specifying the number of threads that are synchronizing on the barrier, and set up threads to perform tasks and wait at the barrier until all the threads reach the barrier. When the last thread arrives at the barrier, all the threads resume execution.
See Parallelizing a Loop on a Shared-Memory Parallel Computer for more about barrier synchronization.
Use pthread_barrier_init(3C) to allocate resources for a barrier and initialize its attributes.
int pthread_barrier_init(pthread_barrier_t *barrier,
const pthread_barrierattr_t *restrict attr,
unsigned count);#include <pthread.h> pthread_barrier_t barrier; pthread_barrierattr_t attr; unsigned count; int ret; ret = pthread_barrier_init(&barrier, &attr, count);
The pthread_barrier_init() function allocates any resources required to use the barrier referenced by barrier and initializes the barrier with attributes referenced by attr. If attr is NULL, the default barrier attributes are used; the effect is the same as passing the address of a default barrier attributes object. The count argument specifies the number of threads that must call pthread_barrier_wait() before any of them successfully return from the call. The value specified by count must be greater than 0.
pthread_barrier_init() returns zero after completing successfully. Any other return value indicates that an error occurred. If the following condition occurs, the function fails and returns the corresponding value.
EINVAL
Description: The value specified by count is equal to 0, or the value specified by attr is invalid
EAGAIN
Description: The system lacks the necessary resources to initialize another barrier.
ENOMEM
Description: Insufficient memory exists to initialize the barrier.
EBUSY
Description: There was an attempt to destroy a barrier while it is in use (for example, while being used in a pthread_barrier_wait() call) by another thread.
Use pthread_barrier_wait(3C) to synchronize threads at a specified barrier. The calling thread blocks until the required number of threads have called pthread_barrier_wait() specifying the barrier. The number of threads is specified in the pthread_barrier_init() function.
When the required number of threads have called pthread_barrier_wait() specifying the barrier, the constant PTHREAD_BARRIER_SERIAL_THREAD is returned to one unspecified thread and 0 is returned to each of the remaining threads. The barrier is then reset to the state it had as a result of the most recent pthread_barrier_init() function that referenced it.
int pthread_barrier_wait(pthread_barrier_t *barrier);
#include <pthread.h> pthread_barrier_t barrier; int ret; ret = pthread_barrier_wait(&barrier);
When pthread_barrier_wait() completes successfully, the function returns PTHREAD_BARRIER_SERIAL_THREAD, which is defined in pthread.h, for one arbitrary thread synchronized at the barrier. The function returns zero for each of the other threads. Otherwise an error code is returned.
EINVAL
Description: The value specified by barrier does not refer to an initialized barrier object.
When a barrier is no longer needed, it should be destroyed. Use the pthread_barrier_destroy(3C) function to destroy the barrier referenced by barrier and release any resources used by the barrier.
int pthread_barrier_destroy(pthread_barrier_t *barrier);
#include <pthread.h> pthread_barrier_t barrier; int ret; ret = pthread_barrier_destroy(&barrier);
pthread_barrier_destroy() returns zero after completing successfully. Any other return value indicates that an error occurred. If the following condition occurs, the function fails and returns the corresponding value.
EINVAL
Description: Indicates that the value of barrier was not valid.
EBUSY
Description: An attempt was made to destroy a barrier while it is in use (for example, while being used in a pthread_barrier_wait() by another thread.
The pthread_barrierattr_init(3C) function initializes a barrier attributes object attr with the default values for the attributes defined for the object by the implementation. Currently, only the process-shared attribute is provided, and the pthread_barrierattr_getpshared() and pthread_barrierattr_setpshared() functions are used to get and set the attribute.
After a barrier attributes object has been used to initialize one or more barriers, any function affecting the attributes object (including destruction) does not affect any previously initialized barrier.
int pthread_barrierattr_init(pthread_barrierattr_t *attr);
#include <pthread.h> pthread_barrierattr_t attr; int ret; ret = pthread_barrierattr_init(&attr);
pthread_barrierattr_init() returns zero after completing successfully. Any other return value indicates that an error occurred. If the following condition occurs, the function fails and returns the corresponding value.
ENOMEM
Description: Insufficient memory exists to initialize the barrier attributes object.
The pthread_barrierattr_setpshared() function sets the process-shared attribute in an initialized attributes object referenced by attr. The process-shared attribute can have the following values:
The barrier can only be operated upon by threads created within the same process as the thread that initialized the barrier. This is the default value of the process-shared attribute.
The barrier can be operated upon by any thread that has access to the memory where the barrier is allocated.
int pthread_barrierattr_setpshared(pthread_barrierattr_t *attr, int pshared);
pthread_barrierattr_setpshared() returns zero after completing successfully. Any other return value indicates that an error occurred. If the following condition occurs, the function fails and returns the corresponding value.
EINVAL
Description: Indicates that the value of attr was not valid, or the new value specified for the pshared is not valid.
The pthread_barrierattr_getpshared(3C) function obtains the value of the process-shared attribute from the attributes object referenced by attr. The value is set by the pthread_barrierattr_setpshared() function.
int pthread_barrierattr_getpshared(const pthread_barrierattr_t *restrict attr,
int *restrict pshared);
pthread_barrierattr_getpshared() returns zero after completing successfully, and stores the value of the process-shared attribute of attr into the object referenced by the pshared parameter. Any other return value indicates that an error occurred. If the following condition occurs, the function fails and returns the corresponding value.
EINVAL
Description: Indicates that the value of attr was not valid.
The pthread_barrierattr_destroy() function destroys a barrier attributes object. A destroyed attr attributes object can be reinitialized using pthread_barrierattr_init().
After a barrier attributes object has been used to initialize one or more barriers, destroying the object does not affect any previously initialized barrier.
#include <pthread.h> int pthread_barrierattr_destroy(pthread_barrierattr_t *attr);
pthread_barrierattr_destroy() returns zero after completing successfully. Any other return value indicates that an error occurred. If the following condition occurs, the function fails and returns the corresponding value.
EINVAL
Description: Indicates that the value of attr was not valid.
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