From: thierry wilmot <wilmot@...>
Date: 2003-09-12T04:33:44+09:00
Subject: Re: stdout in embedded ruby in win32

First , thanks all for your answers, ruby community is great !

Simon Strandgaard : I try to redicrect $defout, $deferr, it no works 
better and  Ruby interpetor tell me these variables will now be obslete.

Zane Dodson : Ok, I think I have here a beginning of answer. I compile 
my app in debug mode and link it with msvcrt-ruby18.dll compiled in 
release mode. Dependency walker show me that my app mount msvcrtd.dll 
and msvcrt.dll for ruby's dll. I try to compile ruby in debug mode, and 
all seems to work fine. (I not find an easy way to compile ruby dll in 
debug, so I hack makefile.sub)

Nobu Nakada : Yes, when using Ruby static lib you can call all core ruby 
functions in a more  easiest way than in dll mode, but if you wanna use 
extensions like webrick or drd, you must first found dll/so used by 
there extensions and link them to your app. That a never ending story !



Sean O'Dell wrote:
> nobu.nokada@softhome.net wrote:
> 
>> Hi,
>>
>> At Thu, 11 Sep 2003 06:09:58 +0900,
>> thierry wilmot wrote:
>>
>>> I have just finished to convert my ruby embedded app from static ruby 
>>> lib (msvcrt-ruby18-static.lib) to dll, and have some problems with 
>>> standard stream stdin,stdout,stderr redirection in dll mode. My .exe 
>>> is not compile in console mode, but in windows mode.
>>
>>
>>
>> Link with msvcrt.dll.
>>
>>
>>> a well works code in static lib :
>>>
>>>     freopen("stdout.txt","w+",stdout);
>>>
>>> Does not work in dll mode, cause some unobvious Windows reasons a dll 
>>> have it own std streams, and if your freopen() streams in .exe, they 
>>> will not be redirected in the msvcrt-ruby18.dll
>>
>>
>>
>> Due to the specification of Windows DLL.  And if you want to
>> use extension libraries, you have to use ruby DLL or recompile
>> all libraries to import symbols from your .exe.
> 
> 
> Not sure if this solves your problem Thierry, but here's what I did in 
> my Windows application to "capture" stdio streams used by the Ruby DLL:
> 
> 
> 
> First, in the Ruby .dll, I hacked in these functions:
> 
> 
> 
>   int rb_w32_redirect_stdin(HANDLE pipe)
>   {
>     return dup2(_open_osfhandle((long)pipe, _O_TEXT), 0);
>   }
> 
>   int rb_w32_redirect_stdout(HANDLE pipe)
>   {
>     return dup2(_open_osfhandle((long)pipe, _O_TEXT), 1);
>   }
> 
>   int rb_w32_redirect_stderr(HANDLE pipe)
>   {
>     return dup2(_open_osfhandle((long)pipe, _O_TEXT), 2);
>   }
> 
> 
> 
> ... and exported them.  Then in my application, I call:
> 
> 
> 
>   // thread that continually grabs Ruby's stdout output
>   unsigned long __stdcall stdioReadThread(void* parameter)
>   {
>     DWORD dwRead;
>     char chBuf[READ_THREAD_BUFFER_SIZE];
> 
>     for( ;; )
>     {
>       if(!ReadFile(stdioReadHandle, chBuf, READ_THREAD_BUFFER_SIZE - 1, 
> &dwRead, NULL) || dwRead == 0)
>         break;
>       chBuf[dwRead / sizeof(char)] = '\0';
>       // DO SOMETHING WITH THE BUFFER HERE
>     }
> 
>     return 0;
>   }
> 
> 
> 
>   // create pipe that replaces Ruby's stdout
>   if(CreatePipe(&stdioReadHandle, &stdioWriteHandle, NULL, 0))
>   {
>     dup2(_open_osfhandle((long)stdioWriteHandle, _O_TEXT), 1);
>     dup2(_open_osfhandle((long)stdioWriteHandle, _O_TEXT), 2);
> 
>     stdioReadThreadHandle = CreateThread(NULL, 0, stdioReadThread, 
> outputTextBox, 0, &stdioReadThreadID);
>   }
> 
> 
> 
>   // then call init, and re-assign Ruby's stdout handle
>   ruby_init();
>   rb_w32_redirect_stdout(GetStdHandle(STD_OUTPUT_HANDLE));
> 
> 
> 
> The read thread will basically "sleep" on the pipe until Ruby sends 
> output to the stdout handle.  When it wakes up, it starts pulling from 
> the pipe.  The example above basically does nothing, but in my 
> application, I sent the output to a textbox to simulate an output 
> console.  You could modify the read thread to do whatever you want with 
> the output.
> 
> Hope that helps ... someone ...
> 
>     Sean O'Dell
>