knoppix@Microknoppix:/mnt-system/lx/test$ gcc -D_REENTRANT -lpthread -o testcondout testcondout.c
knoppix@Microknoppix:/mnt-system/lx/test$ ./testcondout
please input an integer:(<=1000)26
time out
time out
1/1 finished,push 1.0000000000
1/2 finished,push 0.5000000000
1/3 finished,push 0.3333333333
1/4 finished,push 0.2500000000
1/5 finished,push 0.2000000000
time out
1/6 finished,push 0.1666666667
1/7 finished,push 0.1428571429
1/8 finished,push 0.1250000000
1/9 finished,push 0.1111111111
1/10 finished,push 0.1000000000
time out
1/11 finished,push 0.0909090909
1/12 finished,push 0.0833333333
1/13 finished,push 0.0769230769
1/14 finished,push 0.0714285714
1/15 finished,push 0.0666666667
1/1:1.0000000000 added result 1.0000000000
1/2:0.5000000000 added result 1.5000000000
1/3:0.3333333333 added result 1.8333333333
1/4:0.2500000000 added result 2.0833333333
1/5:0.2000000000 added result 2.2833333333
1/6:0.1666666667 added result 2.4500000000
1/7:0.1428571429 added result 2.5928571429
1/8:0.1250000000 added result 2.7178571429
1/9:0.1111111111 added result 2.8289682540
1/10:0.1000000000 added result 2.9289682540
1/11:0.0909090909 added result 3.0198773449
1/12:0.0833333333 added result 3.1032106782
1/13:0.0769230769 added result 3.1801337551
1/14:0.0714285714 added result 3.2515623266
1/15:0.0666666667 added result 3.3182289932
*******1/1:1.0000000000 computed result 1.0000000000
*******1/2:0.5000000000 computed result 0.5000000000
*******1/3:0.3333333333 computed result 0.8333333333
*******1/4:0.2500000000 computed result 0.5833333333
*******1/5:0.2000000000 computed result 0.7833333333
*******1/6:0.1666666667 computed result 0.6166666667
*******1/7:0.1428571429 computed result 0.7595238095
*******1/8:0.1250000000 computed result 0.6345238095
*******1/9:0.1111111111 computed result 0.7456349206
*******1/10:0.1000000000 computed result 0.6456349206
*******1/11:0.0909090909 computed result 0.7365440115
*******1/12:0.0833333333 computed result 0.6532106782
*******1/13:0.0769230769 computed result 0.7301337551
*******1/14:0.0714285714 computed result 0.6587051837
*******1/15:0.0666666667 computed result 0.7253718504
===============compute finish!=========== result:0.7253718504
1/16 finished,push 0.0625000000
1/17 finished,push 0.0588235294
1/18 finished,push 0.0555555556
1/19 finished,push 0.0526315789
1/20 finished,push 0.0500000000
1/16:0.0625000000 added result 3.3807289932
1/17:0.0588235294 added result 3.4395525226
1/18:0.0555555556 added result 3.4951080782
1/19:0.0526315789 added result 3.5477396571
1/20:0.0500000000 added result 3.5977396571
1/21 finished,push 0.0476190476
1/22 finished,push 0.0454545455
1/23 finished,push 0.0434782609
1/24 finished,push 0.0416666667
1/25 finished,push 0.0400000000
time out
*******1/16:0.0625000000 computed result 0.6628718504
*******1/17:0.0588235294 computed result 0.7216953798
*******1/18:0.0555555556 computed result 0.6661398242
*******1/19:0.0526315789 computed result 0.7187714032
*******1/20:0.0500000000 computed result 0.6687714032
*******1/21:0.0476190476 computed result 0.7163904508
*******1/22:0.0454545455 computed result 0.6709359053
*******1/23:0.0434782609 computed result 0.7144141662
*******1/24:0.0416666667 computed result 0.6727474995
*******1/25:0.0400000000 computed result 0.7127474995
===============compute finish!=========== result:0.7127474995
1/21:0.0476190476 added result 3.6453587048
1/22:0.0454545455 added result 3.6908132502
1/23:0.0434782609 added result 3.7342915111
1/24:0.0416666667 added result 3.7759581778
1/25:0.0400000000 added result 3.8159581778
1/26 finished,push 0.0384615385
time out
time out
*******1/26:0.0384615385 computed result 0.6742859611
===============compute finish!=========== result:0.6742859611
1/26:0.0384615385 added result 3.8544197162
================add finish!============ result:3.8544197162
2个线程完成累加和累加减运算(其中一个采用超时等待条件信号,另一个采用等待条件信号),n个线程完成计算每个符点数
#include <pthread.h> #include <bits/pthreadtypes.h> #include <stdio.h> #include <stdlib.h> #include <errno.h> #define MAXS 1000 #define MAXTDS 5 //线程池大小 double myjg[MAXS+1];//计算结果存放位置 int max; pthread_mutex_t eventlock; //互斥锁 pthread_cond_t myevent; //条件变量 pthread_t threads[MAXTDS+2]; //线程池,完成1/n计算 int isend=0; int done; void *mycomp(void *x){//计算1/i的结果,计算结果放在一个数组中。 int i=0; int rc; while (1){ pthread_mutex_lock(&eventlock); if (isend){ pthread_mutex_unlock(&eventlock); break; } i=myjg[0];//myjg[0]存放着线程已经计算到的i。 if (i<max){ i++; myjg[0]=i; } if (i==max){//最后一个数 myjg[i]=(1/(double)i); isend=1; printf("1/%d finished,push %.10f\n",i,myjg[i]); fflush(stdout); pthread_mutex_unlock(&eventlock); sleep(3); rc=pthread_cond_signal(&myevent);//广播信号,多个任务不被阻塞,多个任务竞争互斥锁的所有权。也可以使用pthread_cond_signal(&event);发送信号,这样只有一个线程不被阻塞,其它线程都被阻塞。 if (rc){ perror("pthread_cond_broadcast"); fflush(stdout); } sleep(2); break; } //开始计算 myjg[i]=(1/(double)i); printf("1/%d finished,push %.10f\n",i,myjg[i]); fflush(stdout); pthread_mutex_unlock(&eventlock); if (!(i%MAXTDS)){ sleep(3); pthread_cond_broadcast(&myevent);//广播信号,多个任务不被阻塞,多个任务竞争互斥锁的所有权。也可以使用pthread_cond_signal(&event);发送信号,这样只有一个线程不被阻塞,其它线程都被阻塞。 sleep(3); } } pthread_exit(NULL); } void *myprint1(void *xx){//读取数组,将计算结果累加,最终完成1/1+1/2+1/3+......+1/n的计算,使用超时等待 int maxi; int curj=1; double jg=0; int rc; struct timeval now;//使用微秒 struct timespec timeout; //使用纳秒 while(curj<=max) { //取当前时间 // 深未来技术http://deepfuture.iteye.com/ gettimeofday(&now); //准备时间间隔 timeout.tv_sec=now.tv_sec+1; timeout.tv_nsec=now.tv_usec*1000; maxi=0; pthread_mutex_lock(&eventlock);//用于条件变量的互斥,条件变量就是一个用来发送事件发生信号的信号量 rc=pthread_cond_timedwait(&myevent,&eventlock,&timeout);//在等待条件变量myevent的发生,超时就返回,不再等待。条件变量必须与一个互斥锁eventlock相关联,条件变量不提供锁定,必须有一个互斥锁eventlock配合。 //互斥锁eventlock在调用wait前应锁定,然后在wait期间,互斥量eventlock被解锁。挂起线程执行,直到条件变量myevent收到信号 if (rc==0){ // 深未来技术http://deepfuture.iteye.com/ maxi=myjg[0]; fflush(stdout); pthread_mutex_unlock(&eventlock); for (;curj<=maxi;curj++) { // 深未来技术http://deepfuture.iteye.com/ jg+=myjg[curj]; printf("1/%d:%.10f added result %.10f\n",curj,myjg[curj],jg); fflush(stdout); } } else if (rc==ETIMEDOUT){//TIMEOUT printf("time out\n"); fflush(stdout); pthread_mutex_unlock(&eventlock); continue; } else { // 深未来技术http://deepfuture.iteye.com/ perror("pthread_cond_wait"); fflush(stdout); pthread_mutex_unlock(&eventlock); continue; } } printf("================add finish!============ result:%.10f\n",jg);//输出累加结果。 fflush(stdout); pthread_exit(NULL); } void *myprint2(void *xx){//读取数组,将计算结果完成1/1+1/2-1/3+1/4-1/5......的计算 int maxi=0; int curi=1; double jg=0; int fh=1; int rc; while(curi<=max) { maxi=0; sleep(2); pthread_mutex_lock(&eventlock);//用于条件变量的互斥,条件变量就是一个用来发送事件发生信号的信号量 rc=pthread_cond_wait(&myevent,&eventlock);//在等待条件变量myevent的发生。条件变量必须与一个互斥锁eventlock相关联,条件变量不提供锁定,必须有一个互斥锁eventlock配合。 //互斥锁eventlock在调用wait前应锁定,然后在wait期间,互斥量eventlock被解锁。挂起线程执行,直到条件变量myevent收到信号 // 深未来技术http://deepfuture.iteye.com/ if (rc==0){ maxi=myjg[0]; fflush(stdout); pthread_mutex_unlock(&eventlock); while (curi<=maxi){ jg+=fh*myjg[curi]; printf("*******1/%d:%.10f computed result %.10f\n",curi,myjg[curi],jg); fflush(stdout); fh=-fh; curi++; } printf("===============compute finish!=========== result:%.10f\n",jg);//输出累加结果 fflush(stdout); } else{//error perror("pthread_cond_wait"); fflush(stdout); pthread_mutex_unlock(&eventlock); continue; } } pthread_exit(NULL); } int main(){ //计算1+1/2+1/3+......和1+1/2-1/3+1/4-1/5...... pthread_mutex_init(&eventlock,NULL); pthread_cond_init(&myevent,NULL); int i =0; printf("please input an integer:(<=%d)",MAXS); while (scanf("%d",&max),max>MAXS){//n的最大值 printf("please input an integer:(<=%d)",MAXS); }; //深未来技术http://deepfuture.iteye.com/ myjg[0]=0; pthread_create(&(threads[i]),NULL,myprint1,(void *)&i); sleep(1); i++; pthread_create(&(threads[i]),NULL,myprint2,(void *)&i); sleep(1); i++; for (;i<=MAXTDS;i++){ pthread_create(&(threads[i]),NULL,mycomp,(void *)&i); sleep(1); } sleep(MAXTDS*2*(i/10+1)); //wait...... pthread_mutex_destroy(&eventlock); return(0); }