ANONYMOUS wrote: Yes, permitted, because they are both 'core' in the C11 snd Python-3.12 standards, so no external libraries or modules required. However, you'll very likely find that using threads makes your program more complicated to design (and debug) than just using the select() or poll() system calls. At the 'heart' of a threads library used for I/O is a call to select() or poll() to determine if any thread can execute without blocking for the I/O. In our project, each thread has nothing to do, nothing to calculate, while waiting for I/O to be ready or complete, so you've employed a layer of 'nothingness' where the whole process will still just block waiting for I/O, because it has nothing else to do.