Re: [Mingw-users] Known? fdopen(0,"rb") fails to achieve binary mode

[<dan...@ya...>]

 --- Soren Andersen <sor...@sp...> wrote: > Hello,
> 
> Is it a known issue that using the gcc-win32 ports (MinGW for sure,
> Cygwin maybe), the ANSI C library call fdopen() is buggy or weird?
> 


Believe it or not, fdopen is not in ANSI standard.  So, you really can't
call any implementation-specific behaviour a bug or a feature or a wierd. 


> Testcase: try the arguments to fdopen thusly:
>    fdopen ( fileno(stdin), "rb" );
> as would happen if one was trying to handle redirection (anon pipe or
> <). This stdin redirected from another program's stdout will NOT be in
> binary mode, it will be in text mode, and the calling program will
> likely error if it is requiring a binary read.
>
> I've seen programmers do some of this:
> #ifdef WIN32
> #  define USE_SETMODE 1
> #endif
> .
> .
> .
> #ifdef USE_SETMODE
>    setmode( fileno(stdin), O_BINARY );
> #endif
> 
Yup thats what I do too.

> In order to compensate for this. Is this special case really a bug, or
> is it a technicality, something like "because the stdout is already
> open, we aren't technically opening a new file descriptor, but rather
> just referring to an existing one, so we don't call this a bug [maybe
> we call it 'one of the many extraordinary pleasures of working on
> windoze']"?

You may also want to look at freopen, which is part of the pleasures of
working with ANSI.

Danny

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