unix 利用fork 和sleep 实现的排序，主要是练习 apue chapter 10 fork 和 execlp

//sl.c单个sleep#include<stdio.h>int main(int argc,char*argv[]){if(argc<2){printf("error argc.\n");exit(0);}sleep(atoi(argv[1]));printf("%s\n",argv[1]);return 0;}

#include<stdio.h>#include<sys/types.h>int main(int argc,char*argv[]){pid_t pid;printf("fork main begin.\n");for(int i=1;i<argc;i++){if((pid=fork())<0){printf("fork error.\n");exit(0);}if(pid==0){if(execlp("./sl","./sl",argv[i],(char*)0)<0){printf("execlp error.\n");exit(0);}}}for(int i=0;i<argc;i++)wait(NULL);printf("fork main end.\n");return 0;}