Terminates the current thread.
If another thread is waiting for us using
g_thread_join() then the
waiting thread will be woken up and get
retval as the return value
g_thread_exit() with a parameter
retval is equivalent to
retval from the function
func, as given to g_thread_new().
You must only call
g_thread_exit() from a thread that you created
g_thread_new() or related APIs. You must not call
this function from a thread created with another threading library
or or from within a