How do you open stdout in binary mode with D/Phobos?

In C++ you use something like:

setmode(fileno(stdout), O_BINARY);

(I don't even know where to find O_BINARY in core.stdc).

Bye and thank you,
bearophile

On Wed, 03 Jul 2013 20:20:17 -0400, bearophile <bearophileHUGS@lycos.com> wrote:

> How do you open stdout in binary mode with D/Phobos?

Same way you would do it in C.  D uses C's FILE * as it's implementation.

> In C++ you use something like:
>
> setmode(fileno(stdout), O_BINARY);
>
> (I don't even know where to find O_BINARY in core.stdc).

It may not be present, but it's just a number.  Look it up.

-Steve

Steven Schveighoffer:

>> In C++ you use something like:
>>
>> setmode(fileno(stdout), O_BINARY);
>>
>> (I don't even know where to find O_BINARY in core.stdc).
>
> It may not be present, but it's just a number.  Look it up.

Adding a hardcoded magic number in my code isn't very good.

setmode() should be in unistd.h, but I can't import core.stdc.unistd (and I don't find it in std.c.windows.windows).

fileno() should be in std.stdio or core.stdc.stdio, but I can't find it.


In Python I use:

import os, msvcrt
msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)

Bye,
bearophile

On Thursday, 4 July 2013 at 12:28:07 UTC, bearophile wrote:
> Steven Schveighoffer:
>

>
> setmode() should be in unistd.h, but I can't import core.stdc.unistd (and I don't find it in std.c.windows.windows).

core.sys.posix.unistd

setmode isn't actually standard C nor of the Posix standard. It's a BSD thing. Generally, you have to link with libbsd to use it on Posix systems. You won't find it in the standard unistd.h[1].

[1] http://manpages.ubuntu.com/manpages/gutsy/man7/unistd.h.7posix.html

>
> fileno() should be in std.stdio or core.stdc.stdio, but I can't find it.

core.sys.posix.stdio

Mike Parker:

>> setmode() should be in unistd.h, but I can't import core.stdc.unistd (and I don't find it in std.c.windows.windows).
>
> core.sys.posix.unistd

I have tried this on Windows32, and it doesn't find much:

import core.sys.posix.unistd: setmode;
import core.sys.posix.stdio: fileno;
import core.stdc.stdio: stdout;
void main() {
    setmode(fileno(stdout), O_BINARY);
}


On StackOverflow I have seen in C on Windows you use something like:
http://stackoverflow.com/questions/9554252/c-c-is-it-possible-to-pass-binary-data-through-the-console


#include <stdio.h>
#include <fcntl.h>
#include <io.h>
int main() {
   int result = _setmode(_fileno(stdin), _O_BINARY);
   return 0;
}


Trying another way I have seen this:
http://bytes.com/topic/c/answers/213649-how-write-binary-data-stdout

This is supposed to be valid code in C99 (despite binary mode is not guaranteed to work on all systems), this gives no errors in D but gives no output to me:


import core.stdc.stdio: stdout, freopen;
import std.stdio: write;
void main() {
    auto f = freopen(null, "wb", stdout);
    assert(f);
    write("hello\n\n");
}

Maybe it's a good idea to put something portable to do that in Phobos... Or maybe core.stdc.stdio.freopen is just not C99 compliant and should be fixed.

Bye,
bearophile