#include "err.h"

#include <dirent.h>

int main(int argc, char* argv[])

{

  DIR *dp;

  struct dirent *dirp;



  if(argc != 2)

    err_quit("usage: ls directory_name");



  if((dp = opendir(argv[1])) == NULL)

     err_sys("Can't open %s", argv[1]);

  while((dirp = readdir(dp)) != NULL)

    printf("%s\n", dirp->d_name);



  close(dp);

  return 0;

}

#include <stdio.h>

void err_quit(const char *fmt)

{

  printf( "%s\n", fmt);

  

}



void err_sys(const char *f, const char *s)

{

  printf("%s %s\n", f, s);

}

[root@localhost apue]# ./a.out .

.

..

apue

apue.h

rk1.c~

err.h

a.out

fig1.3.c

rk1.c