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Mail Archives: cygwin/2009/03/18/04:43:47

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Date: Wed, 18 Mar 2009 10:43:23 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: _set_fmode?
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On Mar 17 21:15, Charles Wilson wrote:
> Is there a cygwin analogue to the msvc _set_fmode()? That is, a function
> that sets the default mode of fopen, even if you don't explicitly
> specify it "rb" or whatever.
> 
> Obviously, there's "use binary (or text) mounts".  Less obviously, you
> can link against /usr/lib/binary.o (or -lbinmode), or text.o (or
> automode.o or textreadmode.o and the similar .a's).  But I'm looking for
> an actual function call to replace the following code in libarchive:
> 
> +#if defined(_WIN32) && !defined(__CYGWIN__)

The !defined(__CYGWIN__) is not necessary because gcc for Cygwin doesn't
define _WIN32.

>    /* Make sure open() function will be used with a binary mode. */
>    /* on cygwin, we need something similar, but instead link against */
>    /* a special startup object, binmode.o */
>    _set_fmode(_O_BINARY);
>  #endif
> 
> I'm using binmode.o at present, but I'd prefer to just make a func call
> at the same place the WIN32-specific code does.  (FWIW, you can't call
> the w32api _set_fmode() function and expect it to work; the msvc runtime
> and cygwin maintain different default _fmode variables).

Cygwin has no such function call except for the per-descriptor function
setmode (fd, mode).  IMHO using binmode.o is much more elegant.  The
only other choice you have is this:

  extern int _fmode;
  _fmode = O_BINARY;

_fmode is defined in crt0.o so you can simply access it if you like.
But anyway, using binmode.o is much more elegant, IMHO.  I don't see
what speaks against using it.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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