Why is C printing outputs late?

Question

I am currently running a piece of C code on my Raspberry Pi computer. It is a random number generator that reads from a Geiger counter connected to GPIO digital input 18. It mak

Answer 1

By default, output on stdout is line-buffered when it's writing to a terminal. This means that the output will be held in memory until you print a newline or call fflush(stdout) (or the output buffer fills up -- that's typically 4K or 8K characters).

So put fflush(stdout) at the places where you want the accumulated output to be displayed. Or use setbuf(stdout, NULL) to disable buffering entirely.