Cannot compile boost::asio::spawn program using a boost::asio::yield_context

Question

I want to use boost::asio to read in stdout and stderr from multiple boost::process es simultaneously. However, I have compilation issues with boost::asio and could reconstruct the following minimal example that does not compile:

#include <boost/asio.hpp>
#include <boost/asio/spawn.hpp>

int main() {
    boost::asio::io_context ios;
    boost::asio::spawn(ios,
            [](boost::asio::yield_context ctx) {
            });
    ios.run();
    return 0;
}

GCC 10.2.0 with C++17 enabled and linking to boost version 1.72 results in the following:

In file included from /usr/include/boost/coroutine/coroutine.hpp:10,
                 from /usr/include/boost/coroutine/all.hpp:11,
                 from /usr/include/boost/asio/spawn.hpp:19,
                 from [...]/main.cpp:3:
/usr/include/boost/coroutine/asymmetric_coroutine.hpp: In function ‘typename boost::coroutines::pull_coroutine<R>::iterator boost::coroutines::begin(boost::coroutines::pull_coroutine<Arg>&)’
/usr/include/boost/coroutine/asymmetric_coroutine.hpp:2364:17: error: ‘begin’ is not a member of ‘boost’
 2364 | { return boost::begin( c); }

Answer 1

Yeah this was an missing indirect include in a particular version of boost. See it live on wandbox .

Either

• upgrade to boost 1.73, live
• include the relevant headers, also live :

#include <boost/asio.hpp>
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
#include <boost/asio/spawn.hpp>

int main() {
    boost::asio::io_context ios;
    boost::asio::spawn(ios,
            [](boost::asio::yield_context ctx) {
            });
    ios.run();
    return 0;
}