I have 4 files: websocket.hpp
#include <memory>
#include <functional>
namespace boost {
namespace asio {
class io_context;
} // ns asio
} // ns boost
namespace izycoinscppapi {
namespace feedhandler {
struct websockets {
websockets(const websockets &) = delete;
websockets& operator= (const websockets &) = delete;
websockets(websockets &&) noexcept = default;
websockets& operator= (websockets &&) noexcept = default;
using on_message_received_cb = std::function<void(const char *channel, const char *ptr, std::size_t size)>;
websockets(
boost::asio::io_context &ioctx
,std::string host
,std::string port
,on_message_received_cb cb = {}
);
~websockets();
using handle = void *;
void unsubscribe(const handle &h);
void async_unsubscribe(const handle &h);
void unsubscribe_all();
void async_unsubscribe_all();
template<typename F>
handle w_start_subscription(std::string target, std::string payload, F cb);
private:
struct impl;
std::unique_ptr<impl> pimpl;
};
} // ns feedhandler
} // ns izycoinscppapi
#endif
websocket.cpp
websockets::websockets(
boost::asio::io_context &ioctx
,std::string host
,std::string port
,on_message_received_cb cb
)
:pimpl{std::make_unique<impl>(ioctx, std::move(host), std::move(port), std::move(cb))}
{}
websockets::~websockets()
{}
template<typename F>
websockets::handle websockets::w_start_subscription(std::string target, std::string payload, F cb) {
return pimpl->start_subscription(target, payload, std::move(cb));
}
wsapi.hpp
#ifndef __izycoinscppapi__exchanges__binance__wsapi_hpp
#define __izycoinscppapi__exchanges__binance__wsapi_hpp
#include <memory>
#include <functional>
#include <vector>
#include <izycoinscppapi/feedhandler/websocket.hpp>
namespace boost {
namespace asio {
class io_context;
} // ns asio
} // ns boost
namespace izycoinscppapi {
namespace feedhandler {
namespace ws {
struct fh_price_t;
} // ns ws
struct websockets;
} // ns feedhandler
namespace exchanges {
namespace binance {
namespace errors {
struct error_t;
}
namespace ws {
struct book_ticker_t;
struct wsapi {
wsapi(
boost::asio::io_context &ioctx
,std::string host
,std::string port
,feedhandler::websockets::on_message_received_cb cb = {}
);
~wsapi();
// https://github.com/binance/binance-spot-api-docs/blob/master/web-socket-streams.md#individual-symbol-book-ticker-streams
using on_book_received_cb = std::function<bool(const char *fl, int ec, std::string errmsg, book_ticker_t receivedmsg, feedhandler::ws::fh_price_t returnmsg, binance::errors::error_t err)>;
feedhandler::websockets::handle books(std::vector<std::string> pairs, on_book_received_cb cb);
void async_unsubscribe(const feedhandler::websockets::handle &h);
void async_unsubscribe_all();
private:
std::unique_ptr<feedhandler::websockets> pwebsockets;
};
} // ns ws
} // ns binance
} // ns exchanges
} // ns izycoinscppapi
#endif //
wsapi.cpp
feedhandler::websockets::handle wsapi::books(std::vector<std::string> pairs, on_book_received_cb cb) {
std::string target = build_target(pairs, "bookTicker");
std::string payload{""};
return pwebsockets->w_start_subscription<on_book_received_cb>(target, payload, std::move(cb));
}
As you can see, the w_start_subcription function exists in websocket.hpp and websocket.cpp, it is called in wsapi.cpp via the books function call Here is my main.cpp file
auto books_handler = wsapi.books (
selected_pairs,
[&timer1, &output_file] (const char *fl, int ec, std::string errmsg, auto received_msg, auto msg, auto err) {}
);
When I compile with CMake, I get this error
undefined reference to « void* izycoinscppapi::feedhandler::websockets::w_start_subscription<std::function<bool (char const*, int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, izycoinscppapi::exchanges::binance::ws::book_ticker_t, izycoinscppapi::feedhandler::ws::fh_price_t, izycoinscppapi::exchanges::binance::errors::error_t)>
>(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, std::function<bool (char const*, int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, izycoinscppapi::exchanges::binance::ws::book_ticker_t, izycoinscppapi::feedhandler::ws::fh_price_t, izycoinscppapi::exchanges::binance::errors::error_t)>) ».
But the function exists.
I have no idea why I get this error message.
