怎么做查询网站,超级优化基因液,一个简单的网站怎么做,福田网站制作哪家好1、使用两个线程完成两个文件的拷贝#xff0c;分支线程1拷贝前一半#xff0c;分支线程2拷贝后一半#xff0c;主线程回收两个分支线程的资源
#include stdio.h
#include stdlib.h
#include pthread.h
#include fcntl.h
#include uni…
1、使用两个线程完成两个文件的拷贝分支线程1拷贝前一半分支线程2拷贝后一半主线程回收两个分支线程的资源
#include stdio.h
#include stdlib.h
#include pthread.h
#include fcntl.h
#include unistd.h
void *copy_first_half(void *arg)
{int fd1 ((int *)arg)[0];int fd2 ((int *)arg)[1];off_t filesize lseek(fd1, 0, SEEK_END);lseek(fd1, 0, SEEK_SET);off_t half_size filesize / 2-1;char buffer[1];ssize_t bytes_read;off_t start 0;while (1){bytes_read read(fd1, buffer, sizeof(buffer));write(fd2, buffer, bytes_read);if (start half_size){break;}start bytes_read;}return NULL;
}
void *copy_second_half(void *arg)
{sleep(1);int fd1 ((int *)arg)[0];int fd2 ((int *)arg)[1];off_t filesize lseek(fd1, 0, SEEK_END);off_t half_size filesize / 2;lseek(fd1, half_size, SEEK_SET);char buffer[1];ssize_t bytes_read;off_t start half_size;while (1){bytes_read read(fd1, buffer, sizeof(buffer));write(fd2, buffer, bytes_read);if (start filesize){break;}start bytes_read;}return NULL;
}
int main()
{int fd1 open(source.txt, O_RDONLY | O_CREAT, 0664);int fd2 open(destination.txt, O_WRONLY | O_CREAT | O_TRUNC, 0664);if (fd1 -1 || fd2 -1){perror(打开文件出错\n);exit(EXIT_FAILURE);}pthread_t thread1, thread2;int ret1, ret2;//添加文本int arg1[] {fd1, fd2};int arg2[] {fd1, fd2};// 创建第一个线程ret1 pthread_create(thread1, NULL, copy_first_half, (void *)arg1);if (ret1 ! 0){printf(Error creating thread 1\n);return 1;}// 创建第二个线程ret2 pthread_create(thread2, NULL, copy_second_half, (void *)arg2);if (ret2 ! 0){printf(Error creating thread 2\n);return 1;}// 等待两个线程结束pthread_join(thread1, NULL);pthread_join(thread2, NULL);close(fd1);close(fd2);printf(文件复制成功。\n);return 0;
}
