misbehavior of ftell on stdin?

[June Kim <juneaftn at gmail dot com>]

Hello

I run cygwin on Windows XP through rxvt. When I compile and run the
following code:

#include <stdio.h>

main()
{
  printf("isatty=%d\n",isatty(fileno(stdin)));
  char *s=(char *)malloc(1024+1);
  char *s2=(char *)malloc(1024+1);

  fgets(s,1024,stdin);
  free(s);
  printf("stdio = %ld\n", ftell(stdin));

  fgets(s2,1024,stdin);
  free(s2);
  printf("stdio = %ld\n", ftell(stdin));

}

I input "abcdefg" followed by a nl and then "abcdefg" followed by a nl.

$ gcc test1.c

bash ~
$ ./a 
isatty=1
abcdefg
stdio = 0
abcdefg
stdio = 8

As you see, the first ftell's result is wrong. The first fgets is ignored.

Interestingly, when I run cygwin without rxvt(just running bash.exe
from the dos command line) with CYGWIN=notty, the ftell always returns
-1. If CYGWIN=tty, then ftell behaves as in rxvt ; it returns 0 first
and then behaves correct.

Am I missing something?

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