> Printf isn't re-entrant, and they are calling it from multiple threads. This! Simple schedulers generally only allow system calls (such as printf) from the

> Printf isn't re-entrant, and they are calling it from multiple threads. This! Simple schedulers generally only allow system calls (such as printf) from the main thread. If you really want to 'print' from a child thread then send a message to the main thread, asking that it prints the message contents on on behalf of the child thread.