From: bukinm AT inp DOT nsk DOT su (Michael Bukin)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Desperately need help with "fopen"
Date: 10 Apr 1997 04:34:54 GMT
Organization: BINP SD RAS
Lines: 51
Message-ID: <5ihqle$48j@sky.inp.nsk.su>
References: <334B568B DOT DBF AT ife DOT ee DOT ethz DOT ch>
Reply-To: bukinm AT inp DOT nsk DOT su
NNTP-Posting-Host: h-bukin.inp.nsk.su
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

>fopen("test.txt", "r") returns NULL as long as I have this file
>("test.txt") opened with MS Word for Windows. Other programs (emacs,
>editor, notepad and DOS' type) have no problem reading the file!!! As
>soon as I close the file (it's no longer opened with Word) then
>fopen("test.txt", "r") works fine!
>
>It seems there is some file-locking (sharing) mechanism with Win95 but
>shouldn't it be possible to open the file for reading?????????

The following works on Win95 (using explicit sharing):

#include <some headers>

int
main (int _argc, char* _argv[])
{
  char* filename;
  char buffer[1024];
  int handle;
  FILE* file;

  filename = (_argc > 1) ? _argv[1] : "test.txt";
  if (_dos_open (filename, O_RDONLY | SH_DENYNO, &handle))
    {
      perror (filename);
      return 1;
    }
  file = fdopen (handle, "r");
  if (file == 0)
    {
      perror (filename);
      return 1;
    }
  /* Use `file' here.  */
  if ((fgets (buffer, sizeof (buffer), file) == 0)
      && ferror (file))
    {
      perror (filename);
      return 1;
    }
  fprintf (stderr, "%s\n", buffer);
  if (fclose (file))
    {
      perror (filename);
      return 1;
    }
  return 0;
}

BTW, Emacs for dos can't open files already opened in Word
(at least, not on my machine).