thread synchronisation

[jaeho]

Hello,

I am now studying thread synchronisation going through a book.
There are few steps I will follow.
I am kinda stuck on the half way through the instructions.
Here is the problem.


It says I have to make the parent thread prompt the user to hit "enter"(and wait for the user to do so) hint: I may need a second mutex for this.

1. I do not understand why it is can not be done with a single mutex. and how I let the parent thread to wait for the user's input which is a hitting enter.

2. How I notify from the parent the child one the user has hit the enter key.

[Lazydog]

Which book would that be?

[djap]

You could see here https://computing.llnl.gov/tutorials/pthreads/
under the section "Condition variables" you can find some material and example about thread synchronisation and signaling.