From: "Mark E." <snowball3 AT bigfoot DOT com>
To: djgpp-workers AT delorie DOT com
Date: Wed, 24 Jan 2001 19:35:45 -0500
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Subject: Re: filelength and errno patch
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In-reply-to: <3405-Wed24Jan2001222741+0200-eliz@is.elta.co.il>
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> > +   if (_osmajor >= 7 && _osmajor < 10)
> > +   {
> > +     regs.x.ax = 0x71A6;
> > +     regs.x.bx = fhandle;
> Does this work on plain DOS 7 or only on Windows 9X?  If the latter,
> you will need to test _USE_LFN, I think.

I tried it under DOS 7.{whatever} and it doesn't work. So I added the _USE_LFN test. 
Here's a revised patch. Let me know if it and the errno patch are ok.

Index: filelen.c
===================================================================
RCS file: /cvs/djgpp/djgpp/src/libc/posix/sys/stat/filelen.c,v
retrieving revision 1.1
diff -c -p -r1.1 filelen.c
*** filelen.c	1995/03/29 20:55:56	1.1
--- filelen.c	2001/01/24 23:13:55
***************
*** 1,3 ****
--- 1,4 ----
+ /* Copyright (C) 2001 DJ Delorie, see COPYING.DJ for details */
  /* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
  /* This is file FILELEN.C */
  /*
***************
*** 11,16 ****
--- 12,21 ----
  #include <errno.h>
  #include <dpmi.h>
  #include <libc/dosio.h>
+ #include <go32.h>
+ #include <sys/farptr.h>
+ #include <dos.h>
+ #include <fcntl.h>
  
  long __filelength(int);
  
*************** __filelength(int fhandle)
*** 21,26 ****
--- 26,56 ----
    unsigned short fpos_high, fpos_low;
    long           retval;
  
+   /* Use the LFN API when available to get the file length.  */
+   if (_osmajor >= 7 && _osmajor < 10 && _USE_LFN)
+   {
+     regs.x.ax = 0x71A6;
+     regs.x.bx = fhandle;
+     regs.x.ds = __tb >> 4;
+     regs.x.dx = 0;
+     regs.x.flags |= 1;
+     __dpmi_int(0x21, &regs);
+     
+     if ((regs.x.flags & 1) == 0)
+     {
+       /* Offset 0x24 contains the low 32-bits of the file size.
+          Offset 0x20 contains the high 32-bits.  */
+       retval = _farpeekl(_dos_ds, __tb + 0x24);
+ 
+       if (_farpeekl(_dos_ds, __tb + 0x20) != 0)
+       {
+         errno = EOVERFLOW;
+         return -1L;
+       }
+       return retval;
+     }
+   }
+   
    /* Remember the current file position, so we can return there
       later.  */
    regs.x.ax = 0x4201;      /* set pointer from current position */