To build, just execute "make". You might have to link it with the rt library using "-lrt" if linking fails.
"make clean" to clean the binaries.

Steps to run:-

Execute: (./p1 &);(./p2)

Output:

$ (./p1 &);(./p2)
AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz