2024.4.21

多进程实现拷贝

#include <myhead.h>
//定义结构体
typedef struct INFO
{const char *src_file;const char *dest_file;int mv;int size;}info_t;//获取源文件的大小并且创建目标文件
int size_creat(const char *src_file,const char *dest_file)
{//获取源文件的大小（字节）int src_fd = open(src_file,O_RDONLY);if(-1 == src_fd){perror("open error");return -1;}int size = lseek(src_fd,0,SEEK_END);close(src_fd);//创建目标文件int dest_fd = open(dest_file,O_WRONLY | O_CREAT | O_TRUNC,0666);if(-1 == dest_fd){perror("open error");return -1;}close(dest_fd);return size;
}//复制源文件内容到目标文件内容中
void *cp(void *arg)
{//强制类型转换info_t info = *(info_t *)arg;int src_fd = 0;int dest_fd = 0;//打开源文件if(-1 == (src_fd = open(info.src_file,O_RDONLY))){perror("open error");pthread_exit(NULL);}//打开目标文件if(-1 == (dest_fd = open(info.dest_file,O_WRONLY))){perror("open error");pthread_exit(NULL);}//定位光标lseek(src_fd,info.mv,SEEK_SET);lseek(dest_fd,info.mv,SEEK_SET);int ret = 0;int num = 0;char buf[64] = {0};while (1){ret = read(src_fd,buf,sizeof(buf));if(0 == ret){break;}num += ret;if(num > info.size){write(dest_fd,buf,info.size - (num - ret));break;}write(dest_fd,buf,ret);}//关闭文件close(src_fd);close(dest_fd);}int main(int argc, char const *argv[])
{if(3 != argc){printf("Usage : %s src_file dest_file\n",argv[0]);return -1;}int size = 0;size = size_creat(argv[1],argv[2]);//线程1复制文件内容的前一半//线程2复制文件内容的后一半info_t arg[2] = {{argv[1],argv[2],0,size/2},{argv[1],argv[2],size/2,size - size/2}};pthread_t thread1 = 0;pthread_t thread2 = 0;int ret = 0;//创建线程1if(0 != (ret = pthread_create(&thread1,NULL,cp,&arg[0]))){printf("pthread_create error : errno = [%d] errstr = [%s]\n",ret,strerror(ret));exit(EXIT_FAILURE);}//创建线程2if(0 != (ret = pthread_create(&thread2,NULL,cp,&arg[1]))){printf("pthread_create error : errno = [%d] errstr = [%s]\n",ret,strerror(ret));exit(EXIT_FAILURE);}pthread_join(thread1,NULL);pthread_join(thread2,NULL);return 0;
}