id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
12941	MinGW- Ignore return value from BOOST_INTERLOCKED_EXCHANGE	mattyclarkson@…	viboes	"Warnings are created by MinGW for ignoring the return value in `boost::detail::interlocked_read_acquire`:


{{{
namespace boost
{
    namespace detail
    {
        inline long interlocked_read_acquire(long volatile* x) BOOST_NOEXCEPT
        {
            return BOOST_INTERLOCKED_COMPARE_EXCHANGE(x,0,0);
        }
        inline void* interlocked_read_acquire(void* volatile* x) BOOST_NOEXCEPT
        {
            return BOOST_INTERLOCKED_COMPARE_EXCHANGE_POINTER(x,0,0);
        }
        inline void interlocked_write_release(long volatile* x,long value) BOOST_NOEXCEPT
        {
            BOOST_INTERLOCKED_EXCHANGE(x,value);
        }
        inline void interlocked_write_release(void* volatile* x,void* value) BOOST_NOEXCEPT
        {
            BOOST_INTERLOCKED_EXCHANGE_POINTER(x,value);
        }
    }
}
}}}

My proposed fix it to cast the return value to `void`:


{{{
namespace boost
{
    namespace detail
    {
        inline long interlocked_read_acquire(long volatile* x) BOOST_NOEXCEPT
        {
            return BOOST_INTERLOCKED_COMPARE_EXCHANGE(x,0,0);
        }
        inline void* interlocked_read_acquire(void* volatile* x) BOOST_NOEXCEPT
        {
            return BOOST_INTERLOCKED_COMPARE_EXCHANGE_POINTER(x,0,0);
        }
        inline void interlocked_write_release(long volatile* x,long value) BOOST_NOEXCEPT
        {
            (void)BOOST_INTERLOCKED_EXCHANGE(x,value);
        }
        inline void interlocked_write_release(void* volatile* x,void* value) BOOST_NOEXCEPT
        {
            (void)BOOST_INTERLOCKED_EXCHANGE_POINTER(x,value);
        }
    }
}
}}}

It would also be possible to use `static_cast<void>(...)`:

{{{
namespace boost
{
    namespace detail
    {
        inline long interlocked_read_acquire(long volatile* x) BOOST_NOEXCEPT
        {
            return BOOST_INTERLOCKED_COMPARE_EXCHANGE(x,0,0);
        }
        inline void* interlocked_read_acquire(void* volatile* x) BOOST_NOEXCEPT
        {
            return BOOST_INTERLOCKED_COMPARE_EXCHANGE_POINTER(x,0,0);
        }
        inline void interlocked_write_release(long volatile* x,long value) BOOST_NOEXCEPT
        {
            static_cast<void>(BOOST_INTERLOCKED_EXCHANGE(x,value));
        }
        inline void interlocked_write_release(void* volatile* x,void* value) BOOST_NOEXCEPT
        {
            static_cast<void>(BOOST_INTERLOCKED_EXCHANGE_POINTER(x,value));
        }
    }
}
}}}"	Support Requests	closed		thread	Boost 1.63.0	Problem	worksforme