Many years ago, when there was no MSN and not even think about WhatsApp, the administrators of Linux / Unix servers had to have constant communication with the people who were connected to those servers (since they were multi-user systems, users connected through " silly terminals "). The following program is a chat between users of these systems connected to the same server. The base code belongs to the author Francisco Manuel Marquez García, from the book "Unix: Programacion Avanzada".
Download the .c files and compile.
$ gcc -o llamar-a llamar_a_hilos.c -lpthread
$ gcc -o responder-a responder_a_hilos.c -lpthread $ ./llamar-a 'USER'
$ ./responder-a 'USER'
