主要运用了进程创建 mmap映射区 等知识点
#include<stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <sys/wait.h>int main(){int new_fd,old_fd,i;long int size;char *p_old, *p_new;pid_t pid;old_fd = open("src.txt", O_RDWR,0644);//源文件 自己设定if (old_fd < 0){perror("open error\n");exit(1);}size = lseek(old_fd, 0, SEEK_END);p_old = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, old_fd, 0);
//////////////////////////////////////////new_fd = open("result", O_RDWR | O_CREAT | O_TRUNC, 0644);if (new_fd < 0){perror("open error\n");exit(1);}ftruncate(new_fd, size);p_new = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, new_fd, 0);
/////////////////////////////////////////////size = lseek(old_fd, 0, SEEK_END);long int cut = size / 5;//进程为5long int yu = size % 5;//for(i=0; i<5; i++){pid = fork();if(pid == 0)break;}if(i<=3){printf("pid = %d\n", getpid());memcpy(p_new+i*cut,p_old+i*cut,cut);}else if(i==4){printf("pid = %d\n", getpid());memcpy(p_new+i*cut,p_old+i*cut,cut+yu);}else{int j;pid_t pid2;for(j=0; j<5;j++){while((pid2=waitpid(-1, NULL,WNOHANG)) == 0 && pid2 != -1);printf("---pid2=%d\n", pid2);}}return 0;
}