To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: chmod() corrupts file handle
Date: Sun, 11 Dec 94 14:06:17 +0200
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>

Somebody reported here that his file handle was corrupted by
a call to chmod(), and that he saw an error when he later called
close().

I've lost that posting, but it seems that I don't have that
problem.  A short program attached to this message runs OK
when compiled both by Borland C 3.1 and DJGPP 1.12m2.

Perhaps the original poster could give more details about the
problem he is experiencing, as it seems to be at least not as
general as the original message implied.

Of course, an obvious question that I would ask anybody who writes
for DOS is: why bother about f?chmod() at all?  It seldom makes any
sense in DOS anyway, so why not just #ifdef it out?

-------------------- cut here ---------------------------
#include <stdio.h>
#include <stdlib.h>

#ifdef  __TURBOC__
#include <io.h>
#else
#include <osfcn.h>
#endif

#include <fcntl.h>
#include <sys/stat.h>

void main(int argc, char *argv[])
{
  if (argc > 1)
    {
      char *file = argv[1];
      int   fh   = open(file, O_RDONLY);

      if (fh == -1)
        {
          perror(file);
          exit(1);
        }

      if (chmod(file, S_IREAD))
        {
          perror("chmod");
          exit(1);
        }

      if (close(fh))
        {
          perror("close");
          exit(1);
        }

      exit(0);
    }
  fprintf(stderr, "Usage: %s file\n", argv[0]);
  exit(2);
}