/*-------------------------------------------------------------------*/
/* testdup.c                                                         */
/* The dup system call.                                              */
/*-------------------------------------------------------------------*/
/* Error handling code omitted.                                      */
/*-------------------------------------------------------------------*/

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>

int main(int argc, char *argv[])
{
   int iFd;
   int iOldFd1;
   int iOldFd0;
   char pcBuffer[6];

   /* Write "hello" to a file named tempfile. */

   iFd = creat("tempfile", 0644);

   iOldFd1 = dup(1);

   close(1);
   dup(iFd);
   close(iFd);

   printf("hello");

   close(1);
   dup(iOldFd1);
   close(iOldFd1);

   /* Read "hello" from a file named tempfile. */

   iFd = open("tempfile", O_RDONLY);

   iOldFd0 = dup(0);

   close(0);
   dup(iFd);
   close(iFd);

   scanf("%s", pcBuffer);

   close(0);
   dup(iOldFd0);
   close(iOldFd0);

   /* Print the data to verify that the previous worked. */

   printf("%s\n", pcBuffer);
   return 0;
}


/* Sample execution:

--> gcc -Wall -ansi -pedantic -o testdup testdup.c
--> testdup
hello
-->

*/