fork函数的使用【学习笔记】

 #include "apue.h"

 int globvar = ;
 char buf[] = "a write to stdout\r\n";

 int main(void)
 {
     int var;
     pid_t pid;

     var = ;
     if(write(STDOUT_FILENO,buf,sizeof(buf)-) != sizeof(buf) -)
         err_sys("write error\r\n");
     printf("before fork\r\n");

     if((pid = fork()) < ){
         err_sys("fork error");
     }else if(pid == ){
         globvar++;
         var++;
     }else{
         sleep();
     }
     printf("pid = %ld,glob = %d,var = %d\r\n",(long)getpid(),globvar,var);

     exit();
 }