freopen 리디렉트 해제(...?)

#include <iostream>
 
/* freopen example: redirecting stdout */
#include <sys\stat.h>
#include <io.h>
#include <stdio.h>         // puts()
#include <stdlib.h>
#include <string.h>        // strlen(), memset()
#include <fcntl.h>         // O_RDWR, O_CREAT
#include <unistd.h>        // write(), close(), dup()
#define  BUFF_SIZE   1024
 
 
//#define stdin (&__iob_func()[0])
//#define stdout (&__iob_func()[1])
//#define stderr (&__iob_func()[2])
 
int main(int argc, char** argv) 
{
  FILE* fp = NULL;
  int n = (int)stdout;
  FILE* v = stdout;
 
  n = fileno(stdout);
 
  int x = _get_output_format();
  printf("%x\n", fileno(stdout));
  printf("%x\n", (stdout));
 
  n = (int)stdout;
 
 
  unlink("somefile.txt");
  unlink("myfile.txt");
 
  int fd;
  int save_fd;
  fd = open("somefile.txt", O_CREAT | O_RDWR, S_IREAD | S_IWRITE);
 
  //기존 출력
  save_fd = dup(STDOUT_FILENO);
 
  printf("-----1111111\n");
  puts("puts -----1111111\n");
  dup2((int)fd, STDOUT_FILENO);
  printf("-------0000\n");
  puts("puts -------0000\n");
  close((int)fd);
 
  printf("111111\n");
  puts("puts 111111\n");
 
 
#if 1
  fp = freopen ("myfile.txt","w", (FILE*)stdout);
  printf ("This sentence is redirected to a file.\n");
  printf ("fd       %x\n", fd);
  printf ("save_fd  %x\n", save_fd);
  printf ("stdout   %x\n", stdout);
  printf ("n        %x\n", n);
  fclose ((FILE*)stdout);
#endif
 
 
 
//  fflush((FILE*)save_fd); 멈춘다.
 
 
  printf("22222222\n");
  puts("puts 22222222\n");
 
  dup2(save_fd, STDOUT_FILENO);
  printf("3333333\n");
  puts("puts 3333333\n");
 
  close(save_fd);
 
 
  printf("4444444\n");
  puts("puts 4444444\n");
 
 
//  *(int*)stdout = *(int*)n;
//  *(int*)stdout = *(int*)&n;
//  *(int*)0x77c0aca0 = *(int*)n;
//  *(int*)stdout = *(int*)v;
 
  printf ("file %x\n", n);
  printf ("This sentence is redirected to a file.");
 
  return 0;
}