Linux pipi

Q: How to process input pipe in real time?
A: Linux pipe is buffered (4096? 65536? bytes)
     Solution#1:

Unix buffering delays output to stdout, ruins your day | TurnKey GNU/Linux (turnkeylinux.org)

fflush(stdout);

     Solution#2:

How to turn off buffering of stdout in C - Stack Overflow

c - Is it safe to disable buffering with stdout and stderr? - Stack Overflow   

setvbuf(stdout, NULL, _IONBF, 0);

     Solution#3:

shell - Turn off buffering in pipe - Unix & Linux Stack Exchange

$ stdbuf -o0 application_writes_stdout | application_reads_stdin

     Solution#4:

fifo - Change buffer size of named pipe - Unix & Linux Stack Exchange