How to detect if USART is connected to a console app ?

As i state in the title, what is the best way to detect a connection to a console app on a pc?

I want to include a while loop in my program, that stalls the main program until the user establishes a connection and the program proccedes to the super loop.

Is there a function or a variable that detects the conection and returns true or false respectively ?

SHould i try to create a handshake between the two ?