ICPSEP Content

4. API 比较细节

#include <pthread.h>

int pthread_mutexattr_init (pthread_mutexattr_t *attr)

int pthread_mutexattr_destroy (pthread_mutexattr_t *attr)

int pthread_mutexattr_setpshared (pthread_mutexattr_t *attr, int pshared)

int pthread_mutexattr_getpshared (pthread_mutexattr_t *attr, int *pshared)

pthread_mutexattr_init() 将与这个对象相联系的属性初始化成它们缺省的值。在执行期间，由线索系统分配存储器。pthread_mutexattr_destroy()移走那个存储器，属性对象变得无效。

缺省的属性值为：

pthread_mutexattr_t mattr;

ret = pthread_mutexattr_init (&mattr); /* initialize an attribute to default value */

ret = pthread_mutexattr_destroy (&mattr); /* destroy an attribute */

交互锁变量的范围可以是进程私有或者是系统范围。如果在PTHREAD_SHARE_PROCESS 状态中创建交互锁，而且它存在于共享内存，它可以共享在多于一个进程的线索中。这等价于在mutex_init ()中的USYNC_PROCESS 标识。

pthread_mutexattr_t mattr;

int pshared;

ret = pthread_mutexattr_getpshared (&mattr, &pshared); /* get pshared of mutex */ ret = pthread_mutexattr_setpshared (&mattr, PTHREAD_SHARE_PROCESS);

ret = pthread_mutexattr_setpshared (&mattr, PTHREAD_SHARE_PRIVATE);