/*-------------------------------------------------------------------*/
/* testlowlevelin.c                                                  */
/* The open, read, and close system calls.                           */
/*-------------------------------------------------------------------*/

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

int main(int argc, char *argv[])
{
   int iFd;
   int iRet;
   int iBytesRead;
   char pcBuffer[9];
   int i;

   /* Read "somedata\n" from a file named tempfile. */

   iFd = open("tempfile", O_RDONLY);
   if (iFd == -1) {perror(argv[0]); return 1; }

   iBytesRead = 0;
   while (iBytesRead < 9)
   {
      iRet = read(iFd, pcBuffer + iBytesRead, 9 - iBytesRead);
      if (iRet == -1) {perror(argv[0]); return 1;}
      iBytesRead += iRet;
   }

   iRet = close(iFd);
   if (iRet == -1) {perror(argv[0]); return 1; }

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

   for (i = 0; i < 9; i++)
      putchar(pcBuffer[i]);

   return 0;
}


/* Sample execution:

$ gcc -Wall -ansi -pedantic -o testlowlevelin testlowlevelin.c
$ testlowlevelin
somedata
$

*/