linux进程控制

linux 进程控制主要函数fork, exec, waitpid(exec 函数有7中变体，但经常把它们统称为exec函数)

下面的程序是从标准输入命令并执行

#include "apue.h"#include <sys/wait.h>int main(void){char buf[MAXLINE]; // from apue.hpid_t pid;int status;printf("%%"); // print prompt (printf requires %% to print %)while(fgets(buf, MAXLINE, stdin) != NULL){if(buf[strlen(buf) - 1] == '\n')buf[strlen(buf) - 1] = 0; // replace newline with nullif((pid = fork()) < 0){err_sys("fork error");}else if(0 == pid){ // childexeclp(buf, buf, (char *)0);err_ret("couldn't execute: %s", buf);exit(127);}// parentif((pid = waitpid(pid, &status, 0)) < 0){err_sys("waitpid error");}printf("%% ");}exit(0);}