Date: Mon, 26 Feb 2001 17:30:41 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender: eliz AT is
To: Bruno Haible <haible AT ilog DOT fr>
cc: ST001906 AT HRZ1 DOT HRZ DOT TU-Darmstadt DOT De, djgpp-workers AT delorie DOT com
Subject: Re: gettext pretest available
In-Reply-To: <15002.29723.880411.704219@honolulu.ilog.fr>
Message-ID: <Pine.SUN.3.91.1010226172404.24373E-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Reply-To: djgpp-workers AT delorie DOT com
Errors-To: nobody AT delorie DOT com
X-Mailing-List: djgpp-workers AT delorie DOT com
X-Unsubscribes-To: listserv AT delorie DOT com
Precedence: bulk


On Mon, 26 Feb 2001, Bruno Haible wrote:

> > > # define setmode(fd, mode)      do { \
> > >                                   if (!isatty ((fd))) \
> > >                                     setmode ((fd), mode); \
> > >                                 } while (0)
> > 
> > This will only DTRT if this macro is called _only_ for switching
> > stdin/stdout to binary mode and back.  If you ever call the macro on a
> > handle other than 0 or 1, it might silently do nothing without a good
> > reason.
> 
> Does this mean your isatty() function is broken?

No, I don't think isatty is broken in DJGPP.

> Note that the real
> test, namely INT 44,00 and checking two bits, is not found in your code.
> 
>     #define get_handle_info(handle)  \
>       ({ uint16_t __info;                                                   \
>          __asm__ (                                                          \
>                   " pushl %%ebx ;"                                          \
>                   " movw %1,%%bx ; movw $0x4400,%%ax ; int $0x21 ;"         \
>                   " popl %%ebx "                                            \
>                   : "=d" /* %dx */ (__info)                                 \
>                   : "ri" ((uint16_t)(handle))                               \
>                   : "ax","cx","si","di" /* %eax,%ecx,%esi,%edi */           \
>                  );                                                         \
>          __info;                                                            \
>        })
> 
>    if ((get_handle_info(0) & 0x81) == 0x81)
> 
>    if ((get_handle_info(1) & 0x82) == 0x82)

Where is this code from?  That's not a DJGPP code.

Here's the code of DJGPP's isatty, sans the copyright stuff and the 
include files:

int
isatty(int fd)
{
  __dpmi_regs r;
  r.x.ax = 0x4400;
  r.x.bx = fd;
  __dpmi_int(0x21, &r);
  if ((r.x.ax & 0x83) == 0x83)
    return 1;
  return 0;
}

0x83 checks the character device and stdin/stdout bits of the device 
status word.

Anyway, the issue I referred to was not in isatty, but in setmode.  
setmode treats handle 0 specially, and doesn't look at the stdin/stdout 
bits at all.