c语言 进程控制---创建进程 vfork()函数

#include "stdio.h"#include "unistd.h"#include "sys/types.h"int gvar=2;int main(){pid_t pid;int var = 5;printf("process id:%ld\n",(long)getpid());printf("gvar=%d var=%d\n",gvar,var);pid=vfork();if (pid<0){perror("error");return 1;}else if(pid==0){gvar--;var++;printf("the child  process id:%ld gvar=%d var=%d\n",(long)getpid(),gvar,var);_exit(0);}else{printf("the parent process id:%ld gvar=%d var=%d\n",(long)getpid(),gvar,var);return 0;}}