[Linux] Uninitialized bytes being passed to write()

[urlofmar]

On Linux, valgrind complains about uninitialized bytes being passed to write():

==14689== Syscall param write(buf) points to uninitialised byte(s)
==14689==    at 0x5C6132F: __libc_write (write.c:26)
==14689==    by 0x5C6132F: write (write.c:24)
==14689==    by 0x5656A09: cppcoro::detail::linux::message_queue::enqueue_message(void*, cppcoro::detail::linux::message_type) (linux.cpp:78)
==14689==    by 0x564FB0B: cppcoro::io_service::post_wake_up_event() (io_service.cpp:748)
==14689==    by 0x564F564: cppcoro::io_service::stop() (io_service.cpp:454)
...
==14689==  Address 0x1ffefff044 is on thread 1's stack
==14689==  in frame #1, created by cppcoro::detail::linux::message_queue::enqueue_message(void*, cppcoro::detail::linux::message_type) (linux.cpp:74)

The write() call is in

bool message_queue::enqueue_message(void* msg, message_type type)
{
    message qmsg;
    qmsg.m_type = type;
    qmsg.m_ptr = msg;
    int status = write(m_pipefd[1], (const char*)&qmsg, sizeof(message));
    return status==-1?false:true;
}

where

struct message
{
    enum message_type m_type;
    void* m_ptr;
};

has padding bytes between its two members. These bytes are not initialized in qmsg, but still being written.

So the easiest solution would be to initialize all of qmsg's bytes:

    message qmsg;
+   std::memset(&qmsg, 0, sizeof(qmsg));
    qmsg.m_type = type;
    qmsg.m_ptr = msg;