/“计算 t Pthreads编程代码段*∥/ # include< pthread.h>/#线程控制所需的头文件# # include<smch.h>/“同步操作所需的头文件* extern unsigned microtime 系统计时变量* msigned int fin, start; semaphore- t semaphore: barrier-spin- t barrier;/*同步信号量说明“ double delta, pi: typedef struct/*定义参数结构“/ Int low int high /*定义线程执行的函数并f old child(arg) g蜂arg int low=arg→lw int high=arg→high; double x, part=0.0 for(i=low; i< = high; i++) x=(i+0.5)“ delta; prt+=1.0/(1.0+x“x); psema(& emaphore);/*利用信号量进行互斥累加“/ p+=4.0dlta“pat semaphore - barrier-spin(& barrier);/*线程在完成计算后需bari同步# pthread-exi();/*线程终止蓍/ main\argc, argy int argc char argv[〕 of threads, segments,1i pLhread-t thread Arg“arg