How do I use fstream::open_ostream?

[hashbrown]

I'm learning how to use Microsoft's cpprest sdk and no matter what I do, Visual Studio can't seem to find open_ostream. Is there a specific namespace I need to add before using open_ostream? I've never used open_ostream before.

Thanks!

Btw, I searched for open_ostream and found this explanation: https://msdn.microsoft.com/en-us/library/jj948512.aspx
...but I still don't know how to use it and Visual Studio still can't find it.

// What I'm including.

#include <fstream>
#include <opencv2\core\core.hpp>

#include <cpprest\http_client.h>
#include <cpprest\filestream.h>
#include <cpprest/http_listener.h>            
#include <cpprest/json.h>                     
#include <cpprest/uri.h>                    
#include <cpprest/ws_client.h>              
#include <cpprest/containerstream.h>            
#include <cpprest/interopstream.h>            
#include <cpprest/rawptrstream.h>          
#include <cpprest/producerconsumerstream.h> 

// in the main function, this is where I run into the open_ostream issue...
pplx::task<void> requestTask = std::fstream::open_ostream(U("results.html")).then([=](ostream outFile) 
// removed the rest of the code in order to make this message shorter 

[mbozzi]

There is no such thing as std::fstream::open_ostream() in standard C++.

Don't confuse the Rest SDK stuff with the stuff in the standard namespace.

The bottom of the reference page you linked suggests the name of the function is ::concurrency::streams::open_ostream().

[hashbrown]

Ahhh I feel stupid. I went back to the MS article after reading your post and noticed the namespace. I'll make sure to look more carefully next time. Thanks mbozzi!