[v2][Windows] Cannot redirect stdout to a file

I am using boost process v2 from the 1.86 version of the boost library.

The following code is intended to redirect stdout to a file. It creates the file but the contents of stdout are not written to it; the file size is zero. When I redirect stdout to a pipe, the pipe contains the expected result.

I guessed at how to write the code to redirect stdout to a file, as I could not find any example in the documentation or online. So I have probably not done it right.

#include <boost/process/v2.hpp>
#include <boost/asio/read.hpp>
#include <boost/asio/readable_pipe.hpp>
#include <boost/asio/basic_stream_file.hpp>

namespace proc   = boost::process::v2;
namespace asio   = boost::asio;

std::tuple<int, std::string> execProc(const std::string& exePath, const std::vector<std::string>& args,
    const std::string& outputFilePath)
{
    asio::io_context ctx;

    asio::basic_stream_file<asio::any_io_executor> outStream(ctx, outputFilePath.c_str(), 
        asio::file_base::write_only | asio::file_base::create | asio::file_base::exclusive);

    asio::readable_pipe errPipe{ctx};

    proc::process proc{ ctx, exePath, args, proc::process_stdio{{}, outStream, errPipe}};

    std::string error;
    boost::system::error_code ec;
    auto errLen = asio::read(errPipe, asio::dynamic_buffer(error), ec);
    auto exitCode = proc.wait();
    outStream.close();

    return std::make_tuple(exitCode, std::move(error));
}

boostorg / process

[v2][Windows] Cannot redirect stdout to a file #412