www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.learn - Redirecting C++ ostreams

reply "Jeremy DeHaan" <dehaan.jeremiah gmail.com> writes:
Hey guys,

I have something I am curious about, but haven't had much luck 
with when doing research and experimenting.

Basically, I am working with a library that uses ostreams 
internally and I want to somehow redirect that to what ever 
stderr is pointing to.

The reason I am trying to do this is because I was considering 
the user might want to have some sort of log they want error 
messages written to, and if they redirect stderr to a file I'd 
like the underlying ostreams to be directed to the same location.

Any ideas or suggestions would be welcome!

Thanks in advance
Jun 11 2013
parent reply "Craig Dillabaugh" <cdillaba cg.scs.carleton.ca> writes:
On Wednesday, 12 June 2013 at 04:05:22 UTC, Jeremy DeHaan wrote:

 Hey guys,

 I have something I am curious about, but haven't had much luck 
 with when doing research and experimenting.

 Basically, I am working with a library that uses ostreams 
 internally and I want to somehow redirect that to what ever 
 stderr is pointing to.

 The reason I am trying to do this is because I was considering 
 the user might want to have some sort of log they want error 
 messages written to, and if they redirect stderr to a file I'd 
 like the underlying ostreams to be directed to the same 
 location.

 Any ideas or suggestions would be welcome!

 Thanks in advance


Do you have access to the source code of the library? Or are you
just linking to it?
Jun 12 2013
parent reply "Jeremy DeHaan" <dehaan.jeremiah gmail.com> writes:
On Wednesday, 12 June 2013 at 16:15:08 UTC, Craig Dillabaugh 
wrote:

 Do you have access to the source code of the library? Or are you
 just linking to it?


I do some-what.

I don't want to change the source code of the library itself, but 
I can change the C/C++ code of the binding that is used by D.

If nothing else, I suppose I could write to the ostream directly, 
but I thought that it would be nice to be able to use stderr in 
all of the D code.
Jun 12 2013
parent "Jeremy DeHaan" <dehaan.jeremiah gmail.com> writes:
Not sure if anyone cares too much since I doubt this will come up 
very often, but on the off chance it does I came up with a 
solution that will at least work for me.

In my C/C++ code I created two variables; std::ostringstream 
outputStream and std::string outputString. outputStream is what I 
used to redirect the underlying ostream, and then I made a 
function as follows:

const char* getOutput()
{
     outputString = outputStream.str();

     outputStream.str("");

     return outputString.c_str();
}

And then in my D code(after linking it to my C code) I do one of 
these after I know something was written to the ostream:

stderr.write(text(getOutput()));


This way I can redirect stderr wherever I want and still send the 
contents of the ostream to the same place.
Jun 13 2013