does pthread_join affects concurrently

Question

I want to run all threads concurrently. If I use pthread_join function does it affect running of threads concurrently?

pthread_join(..)

Answer 1

...does it affect running of threads concurrently?

That seems like a strange thing to ask. Technically speaking, Yes. Nothing in thread A can happen concurrently with anything in thread B after thread A calls pthread_join(B, ...).

But that's an obscure, academic way to talk about pthread_join(). The practical way to say the same thing is, pthread_join(B, ...), does not return until thread B is finished.