# Standalone ASIO with Visual Studio 2015

ASIO is a C++ networking library included in Boost C++.

In its standard configuration ASIO relies heavily on Boost, however what if you don’t want to have Boost as a dependency?

ASIO can be defined as standalone in your project settings.

This page says (for MSVC 2012) to define ASIO_STANDALONE, it was not as simple as this for me, below is what I did to use standalone ASIO in VS 2015.

Apparently ASIO will not automatically detect C++11 features available, these need to be specified manually.

In C/C++ Preprocessor Settings, I defined:

ASIO_STANDALONE
ASIO_HAS_STD_ARRAY
ASIO_HAS_CSTDINT
ASIO_HAS_STD_SHARED_PTR
ASIO_HAS_STD_TYPE_TRAITS

ASIO_HAS_STD_FUNCTION
ASIO_HAS_STD_CHRONO

BOOST_ALL_NO_LIB
_WIN32_WINNT=0x0501
_WINSOCK_DEPRECATED_NO_WARNINGS


Some searching lead me to this stackoverflow page which is where the first five ASIO_HAS_* come from.

The remaining three I tracked down manually, by opening the .hpp files that were using boost headers and determining the missing define.

For example, in basic_socket_iostream.hpp ASIO_HAS_VARIADIC_TEMPLATES was undefined and therefore attempting to include boost headers.

/detail/function.hpp

Specifing that these features exist prevents boost from being included.

Now for source errors

In the file random_access_handle_service.hpp there is a single line that always includes boost/config.hpp this needs to be changed when in standalone mode.

My fix:

Lastly there were errors generated by win_iocp_io_service.ipp caused by a missing include for using std::min

My fix:

For the last few defines:

BOOST_ALL_NO_LIB
_WIN32_WINNT=0x0501
_WINSOCK_DEPRECATED_NO_WARNINGS


BOOST_ALL_NO_LIB prevents automatic linking to Boost libraries

_WIN32_WINNT=0x0501 asio generated a warning telling me to defined this, so I did :p

_WINSOCK_DEPRECATED_NO_WARNINGS last step for a successful build

Just for fun here is an example program:

Everything should work swimmingly :D