c++ error saving to file using stream - c++

Question

I'm doing some code where i redirect the output to a file, but i get error using the fstream, ostream, streambuf(). It says that
-"fstream" is ambiguous
-"ostream" is ambiguous
-class "std::basic_ostream>" has no member "streambuf"
-class "std::shared_ptr" has no member "close"
I already search it for includes, installed the lastest version of the casablanca's rest api, ... and i still get those erros.. its missing some include?
Here is the code
#include <sstream>
#include <iostream>
#include <fstream>
#include <cpprest/http_client.h>
#include <cpprest/filestream.h>
#include <cpprest/http_listener.h> // HTTP server
#include <cpprest/json.h> // JSON library
#include <cpprest/uri.h> // URI library
#include <cpprest/ws_client.h> // WebSocket client
#include <cpprest/containerstream.h> // Async streams backed by STL containers
#include <cpprest/interopstream.h> // Bridges for integrating Async streams with STL and WinRT streams
#include <cpprest/rawptrstream.h> // Async streams backed by raw pointer to memory
#include <cpprest/producerconsumerstream.h> // Async streams for producer consumer scenarios
using namespace utility; // Common utilities like string conversions
using namespace web; // Common features like URIs.
using namespace web::http; // Common HTTP functionality
using namespace web::http::client; // HTTP client features
using namespace concurrency::streams; // Asynchronous streams
using namespace web::http::experimental::listener; // HTTP server
using namespace web::experimental::web_sockets::client; // WebSockets client
using namespace web::json;
//Method
auto fileStream = std::make_shared<std::ostream>();
// Open stream to output file.
pplx::task<void> requestTask = fstream::open_ostream(U("results.html")).then([=](ostream outFile) //Error here on the fstrea and ostream
{
*fileStream = outFile;
// Create http_client to send the request.
http_client client(U("http://localhost:53213"));
// Build request URI and start the request.
uri_builder builder(U("/search"));
builder.append_query(U("q"), U("cpprestsdk github"));
return client.request(methods::GET, builder.to_string());
})
// Handle response headers arriving.
.then([=](http_response response)
{
printf("Received response status code:%u\n", response.status_code());
// Write response body into the file.
return response.body().read_to_end(fileStream->streambuf()); //Error here on streambuf
})
// Close the file stream.
.then([=](size_t)
{
return fileStream.close(); //Error on close
});
// Wait for all the outstanding I/O to complete and handle any exceptions
try
{
requestTask.wait();
}
catch (const std::exception &e)
{
printf("Error exception:%s\n", e.what());
}

Answer 1

-"fstream" is ambiguous
-"ostream" is ambiguous
-class "std::basic_ostream>" has no member "streambuf"
You are clashing std:: and casablanca's concurrency::streams namespaces, either make sure they are never pulled in with using in one file or use concurrency::streams explicitly
-class "std::shared_ptr" has no member "close"
but it does not! use -> on your fileStream
EDIT: I think your code is nothing but slightly modified version of official sample, you can just double check that you got it right

Answer 2

I had a similar problem, and indeed it's all to do with the namespace declaration & usage.
The comments above told only half the story.
This is what I ended up with for that application & it works:-
(using VS2019)
//using namespace std;
using namespace concurrency::streams;
stringstreambuf buffer;
auto fileStream = std::make_shared();
pplx::task requestTask = fstream::open_ostream( U("results.html")).then([=](ostream outFile)
{
*fileStream = outFile;
etc . . .