1 #include "apue.h" 2  3  4 int main(int argc,char *argv[]) 5 { 6     struct stat stabuf; 7  8     if(stat("zbzhuang",&stabuf) < 0) 9         err_sys("stat error for foo");10     if(chmod("zbzhuang",(stabuf.st_mode & ~S_IXGRP)|S_ISGID) < 0)11         err_sys("chmod error for foo");12 13     if(chmod("caylin",S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH) < 0)14         err_sys("chmod error for bar");15 16     return 0;17 }